MAX6387XS34D7+中文资料

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MAX6387XS33D7-T中文资料

General DescriptionThe MAX6381–MAX6390 microprocessor (µP) supervisory circuits monitor power supply voltages from +1.8V to +5.0V while consuming only 3µA of supply current at +1.8V. Whenever V CC falls below the factory-set reset thresholds, the reset output asserts and remains assert-ed for a minimum reset timeout period after V CC rises above the reset threshold. Reset thresholds are available from +1.58V to +4.63V, in approximately 100mV incre-ments. Seven minimum reset timeout delays ranging from 1ms to 1200ms are available.The MAX6381/MAX6384/MAX6387 have a push-pull active-low reset output. The MAX6382/MAX6385/MAX6388 have a push-pull active-high reset output,and the MAX6383/MAX6386/MAX6389/MAX6390 have an open-drain active-low reset output. The MAX6384/MAX6385/MAX6386 also feature a debounced manual reset input (with internal pullup resistor). The MAX6387/MAX6388/MAX6389 have an auxiliary input for monitoring a second voltage. The MAX6390 offers a manual reset input with a longer V CC reset timeout period (1120ms or 1200ms) and a shorter manual reset timeout (140ms or 150ms).The MAX6381/MAX6382/MAX6383 are available in 3-pin SC70 packages and the MAX6384–MAX6390 are avail-able in 4-pin SC70 packages.________________________ApplicationsComputers ControllersIntelligent InstrumentsCritical µP and µC Power Monitoring Portable/Battery-Powered Equipment Dual Voltage SystemsFeatureso Factory-Set Reset Threshold Voltages Ranging from +1.58V to +4.63V in Approximately 100mV Increments o ±2.5% Reset Threshold Accuracy Over Temperature (-40°C to +125°C)o Seven Reset Timeout Periods Available: 1ms,20ms, 140ms, 280ms, 560ms, 1120ms, 1200ms (min)o 3 Reset Output OptionsActive-Low Push-Pull Active-High Push-Pull Active-Low Open-Draino Reset Output State Guaranteed Valid Down to V CC = 1Vo Manual Reset Input (MAX6384/MAX6385/MAX6386)o Auxiliary RESET IN(MAX6387/MAX6388/MAX6389)o V CC Reset Timeout (1120ms or 1200ms)/Manual Reset Timeout (140ms or 150ms) (MAX6390)o Negative-Going V CC Transient Immunity o Low Power Consumption of 6µA at +3.6V and 3µA at +1.8V o Pin Compatible withMAX809/MAX810/MAX803/MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/MAX6348, and MAX6711/MAX6712/MAX6713o Tiny 3-Pin SC70 and 4-Pin SC70 PackagesMAX6381–MAX6390SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits________________________________________________________________Maxim Integrated Products1Pin Configurations19-1839; Rev 1; 04/01Ordering InformationOrdering Information continued at end of data sheet.Typical Operating Circuit appears at end of data sheet.Selector Guide appears at end of data sheet.Note:Insert reset threshold suffix (see Reset Threshold table)after "XR" or "XS". Insert reset timeout delay (see Reset Timeout Delay table) after "D" to complete the part number. Sample stock is generally held on standard versions only (seeStandard Versions table). Standard versions have an order increment requirement of 2500 pieces. Nonstandard versions have an order increment requirement of 10,000 pieces.Contact factory for availability of nonstandard versions.*MAX6390 is available with D4 or D7 timing only.For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .M A X 6381–M A X 6390SC70, Single/Dual Low-Voltage, Low-Power µP Reset CircuitsABSOLUTE MAXIMUM RATINGSELECTRICAL CHARACTERISTICSStresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.V CC to GND..........................................................-0.3V to +6.0V RESET Open-Drain Output....................................-0.3V to +6.0V RESET , RESET (Push-Pull Output).............-0.3V to (V CC + 0.3V)MR , RESET IN.............................................-0.3V to (V CC + 0.3V)Input Current (V CC ).............................................................20mA Output Current (All Pins).....................................................20mAContinuous Power Dissipation (T A = +70°C)3-Pin SC70 (derate 2.9mW/°C above +70°C)........235mW 4-Pin SC70 (derate 3.1mW/°C above +70°C)........245mW Operating Temperature Range .........................-40°C to +125°C Storage Temperature Range.............................-65°C to +150°C Lead Temperature (soldering, 10s).................................+300°CMAX6381–MAX6390SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits_______________________________________________________________________________________3M A X 6381–M A X 6390SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits 4______________________________________________________________________________________Typical Operating Characteristics(T A = +25°C, unless otherwise noted.)215436789-40-105-25203550658095110125SUPPLY CURRENT vs. TEMPERATURE(NO LOAD)TEMPERATURE (°C)S U P P L Y C U R R E N T (µA )25292735333137394143-40-105-25203550658095110125POWER-DOWN RESET DELAYvs. TEMPERATURETEMPERATURE (°C)P O W E R -D O W N R E S E T D E L A Y (µs )0.940.980.961.021.001.061.041.08-40-10520-253550658095110125NORMALIZED POWER-UP RESET TIMEOUTvs. TEMPERATUREM A X 6381/90 t o c 03TEMPERATURE (°C)N O R M A L I Z E D R E S E T T I M E O U T P E R I O D0.9900.9851.0150.9950.9901.0001.0051.0101.020-40-10520-253550958011065125M A X 6381/90 t o c 04TEMPERATURE (°C)N O R M A L I Z E D R E S E TT H R E S H O L D NORMALIZED RESET THRESHOLDvs. TEMPERATURE00.40.20.80.61.01.2063912OUTPUT VOLTAGE LOW vs. SINK CURRENTI SINK (mA)V O L (V )01.00.52.01.52.53.00500750250100012501500OUTPUT VOLTAGE HIGH vs. SOURCE CURRENTI SOURCE (µA)V O H (V )45001100010010MAXIMUM TRANSIENT DURATION vs. RESET COMPARATOR OVERDRIVE15050350250500200100400300RESET COMPARATOR OVERDRIVE, V TH - V CC (mV)M A X I M U M T R A N S I E N T D U R A T I O N (µs )3.53.93.74.54.34.14.74.95.35.15.5-40-105-25203550658095110125RESET IN TO RESET DELAYvs. TEMPERATUREM A X 6381/90 t o c 08TEMPERATURE (°C)R E S E T I N D E L A Y (µs )MAX6381–MAX6390SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits_______________________________________________________________________________________5M A X 6381–M A X 6390SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits 6_______________________________________________________________________________________Detailed DescriptionRESET OutputA µP reset input starts the µP in a known state. These µP supervisory circuits assert reset to prevent code execution errors during power-up, power-down, or brownout conditions.Reset asserts when V CC is below the reset threshold;once V CC exceeds the reset threshold, an internal timer keeps the reset output asserted for the reset timeout period. After this interval, reset output deasserts. Reset output is guaranteed to be in the correct logic state for V CC ≥1V.Manual Reset Input (MAX6384/MAX6385/MAX6386/MAX6390)Many µP-based products require manual reset capabil-ity, allowing the operator, a test technician, or external logic circuitry to initiate a reset. A logic low on MR asserts reset. Reset remains asserted while MR is low,and for the reset active timeout period (t RP ) after MR returns high. This input has an internal 63k Ωpullup resistor (1.35k Ωfor MAX6390), so it can be left uncon-nected if it is not used. MR can be driven with TTL or CMOS logic levels, or with open-drain/collector outputs.Connect a normally open momentary switch from MR to G ND to create a manual-reset function; external debounce circuitry is not required. If MR is driven from long cables or if the device is used in a noisy environ-ment, connecting a 0.1µF capacitor from MR to G ND provides additional noise immunity.RESET IN Comparator(MAX6387/MAX6388/MAX6389)RESET IN is compared to an internal +1.27V reference.If the voltage at RESET IN is less than 1.27V, reset asserts. Use the RESET IN comparator as a user-adjustable reset detector or as a secondary power-sup-ply monitor by implementing a resistor-divider at RESET IN (shown in Figure 1). Reset asserts when either V CC or RESET IN falls below its respective threshold volt-age. Use the following equation to set the threshold:V INTH = V THRST (R1/R2 + 1)where V THRST = +1.27V. To simplify the resistor selec-tion, choose a value of R2 and calculate R1:R1 = R2 [(V INTH /V THRST ) - 1]Since the input current at RESET IN is 50nA (max),large values can be used for R2 with no significant loss in accuracy.___________Applications InformationNegative-Going V CC TransientsIn addition to issuing a reset to the µP during power-up,power-down, and brownout conditions, the MAX6381–MAX6390 are relatively immune to short dura-tion negative-going V CC transients (glitches).The Typical Operating Characteristics section shows the Maximum Transient Durations vs. Reset Comparator Overdrive, for which the MAX6381–MAX6390 do not generate a reset pulse. This graph was generated usinga negative-going pulse applied to V CC , starting above the actual reset threshold and ending below it by the magni-tude indicated (reset comparator overdrive). The graph indicates the typical maximum pulse width a negative-going V CC transient may have without causing a reset pulse to be issued. As the magnitude of the transient increases (goes farther below the reset threshold), the maximum allowable pulse width decreases. A 0.1µF capacitor mounted as close as possible to V CC provides additional transient immunity.Ensuring a Valid RESET Output Down to V CC = 0The MAX6381–MAX6390 are guaranteed to operate properly down to V CC = 1V. In applications that require valid reset levels down to V CC = 0, a pulldown resistor to active-low outputs (push/pull only, Figure 2) and a pullup resistor to active-high outputs (push/pull only) will ensure that the reset line is valid while the reset output can no longer sink or source current. This scheme doesnot work with the open-drain outputs of the MAX6383/MAX6386/MAX6389/MAX6390. The resistor value used is not critical, but it must be small enough not to load the reset output when V CC is above the reset threshold. For most applications, 100k Ωis adequate.MAX6381–MAX6390SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits_______________________________________________________________________________________7M A X 6381–M A X 6390SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits 8Selector GuideChip InformationTRANSISTOR COUNT: 647PROCESS: BiCMOS*MR is for MAX6384/MAX6385/MAX6386/MAX6390**RESET IN is for MAX6387/MAX6388/MAX6389( ) are for MAX6382/MAX6385/MAX6388Pin Configurations (continued)MAX6381–MAX6390SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits_______________________________________________________________________________________9Ordering Information(continued)Note:Insert reset threshold suffix (see Reset Threshold table)after "XR" or "XS". Insert reset timeout delay (see Reset Timeout Delay table) after "D" to complete the part number. Sample stock is generally held on standard versions only (seeStandard Versions table). Standard versions have an order increment requirement of 2500 pieces. Nonstandard versions have an order increment requirement of 10,000 pieces.Contact factory for availability of nonstandard versions.*MAX6390 is available with D4 or D7 timing only.M A X 6381–M A X 6390SC70, Single/Dual Low-Voltage, Low-Power µP Reset Circuits 10______________________________________________________________________________________Package InformationSC70, Single/Dual Low-Voltage, Low-Power µP Reset CircuitsMaxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600____________________11©2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.MAX6381–MAX6390Package Information (continued)元器件交易网。

MAX6743XKW中文资料

General DescriptionThe MAX6736–MAX6745 are low-power dual-/triple-voltage microprocessor (µP) supervisors. These devices assert a reset if any monitored supply falls below its factory-trimmed or adjustable threshold and maintain reset for a minimum timeout period after all supplies rise above their thresholds. The integrated dual/triple supervisory circuits significantly reduce size and power compared to separate ICs or discrete com-ponents. The low supply current of 6µA makes these devices ideal for portable equipment.The MAX6736/MAX6737 are dual fixed-voltage µP supervisors with a manual reset input. The MAX6738/MAX6739 have one fixed and one adjustable reset threshold and a manual reset input. The MAX6740/MAX6743 are triple-voltage µP supervisors with two fixed and one user-adjustable reset threshold inputs.The MAX6741/MAX6744 are dual-voltage µP supervi-sors with a power-OK (POK) output ideal for power-supply sequencing. The MAX6742/MAX6745 monitor the primary V CC supply and have an independent power-fail comparator.The MAX6736–MAX6745 monitor I/O supply voltages (V CC 1) from 1.8V to 5.0V and core supply voltages (V CC 2) from 0.9V to 3.3V with factory-trimmed reset threshold voltage options (Table 1). An external adjustable RSTIN input option allows monitoring volt-ages down to 0.5V.A variety of push-pull or open-drain reset outputs along with manual reset input and power-fail input/output fea-tures are available (see the Selector Guide ). The MAX6736–MAX6745 are offered in a space-saving 5-pin SC70 package and operate over the -40°C to +85°C temperature range.ApplicationsFeatureso Dual-/Triple-Supply Reset Voltage Monitors o Precision Factory-Set Reset Thresholds for Monitoring from 0.9V to 5.0Vo Adjustable Reset Input Down to 0.488Vo 150ms and 1200ms (min) Reset Timeout Period Optionso V CC 1 Power-OK Output for Power-SupplySequencing Applications (MAX6741/MAX6744)o Power-Fail Input/Power-Fail Output (MAX6742/MAX6745)o 6µA Supply Current o Tiny SC70 PackageMAX6736–MAX6745Low-Power Dual-/Triple-Voltage SC70 µPSupervisory Circuits________________________________________________________________Maxim Integrated Products1Selector GuideOrdering Information19-2531; Rev 1; 4/03For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .Note:The first “_ _” or “_” are placeholders for the threshold voltage levels of the devices. Desired threshold levels are set by the part number suffix found in Tables 1 and 2. The “_” after the D is a placeholder for the reset timeout period suffix found in Table 3. For example, the MAX6736XKLTD3-T is a dual-volt-age supervisor V TH 1 = 4.625V, V TH 2 = 3.075V, and a 150ms minimum reset timeout period. All devices are available in tape-and-reel only. There is a 2500-piece minimum orderincrement for standard versions (see Table 1). Sample stock is typically held on standard versions only. Nonstandard versions require a minimum order increment of 10,000 pieces. Contact factory for availability.Portable/Battery-Powered Equipment Multivoltage Systems Notebook ComputersControllers PDAsGPS Equipment POS EquipmentOrdering Information continued at end of data sheet.Selector Guide continued at end of data sheet.Pin Configurations appear at end of data sheet.Typical Application Circuits appear at end of data sheet.Functional Diagram appears at end of data sheet.M A X 6736–M A X 6745Low-Power Dual-/Triple-Voltage SC70 µP Supervisory Circuits 2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGSStresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.V CC 1, V CC 2, POK1 to GND......................................-0.3V to +6V Open-Drain RESET , PFO to GND.............................-0.3V to +6V Push-Pull RESET to GND..........................-0.3V to (V CC 1 + 0.3V)MR , RSTIN, PFI to GND............................-0.3V to (V CC 1 + 0.3V)Input/Output Current, All Pins.............................................20mA Continuous Power Dissipation (T A = +70°C)5-Pin SC70 (derate 3.1mW/°C above +70°C)..............247mWOperating Temperature Range ...........................-40°C to +85°C Junction Temperature......................................................+150°C Storage Temperature Range.............................-65°C to +150°C Lead Temperature (soldering, 10s).................................+300°CMAX6736–MAX6745Low-Power Dual-/Triple-Voltage SC70 µPSupervisory Circuits_______________________________________________________________________________________3ELECTRICAL CHARACTERISTICS (continued)M A X 6736–M A X 6745Low-Power Dual-/Triple-Voltage SC70 µP Supervisory Circuits 4_______________________________________________________________________________________ELECTRICAL CHARACTERISTICS (continued)MAX6736–MAX6745Low-Power Dual-/Triple-Voltage SC70 µPSupervisory Circuits_______________________________________________________________________________________5ELECTRICAL CHARACTERISTICS (continued)(V CC = 1.2V to 5.5V, T A = -40°C to +85°C, unless otherwise noted. Typical values are at T A = +25°C.) (Note 1)Note 3:t RD timeout period begins after POK1 timeout period (t POKP ) and V CC 2 ≥V TH 2 (max) (MAX6741/MAX6744).Note 4:Refers to the manual reset function obtained by forcing the RESET output low.Note 5:V CC 1 ≥1.6V.Typical Operating Characteristics(T A = +25°C, unless otherwise noted.)SUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T (µA)6040200-20123456789100-4080SUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T(µA )6040200-20123456789100-4080SUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T (µA )604020-2012345678910-4080M A X 6736–M A X 6745Low-Power Dual-/Triple-Voltage SC70 µP Supervisory Circuits 6_______________________________________________________________________________________NORMALIZED V CC /POK1/MR TIMEOUT PERIOD vs. TEMPERATUREM A X 6736-45 t o c 04TEMPERATURE (°C)N O R M A L I Z E D V C C /P O K 1/M R R E S E T T I M E O U T P E R I O D604020-200.9890.9940.9991.0041.0091.0141.0190.984-4080MAXIMUM V CC 1/V CC 2 TRANSIENT DURATIONvs. RESET THRESHOLD OVERDRIVERESET THRESHOLD OVERDRIVE (mV)M A X I M U M V C C 1/V C C 2 T R A N S I E N T D U R A T I O N (µs )10010100100010,0000101000NORMALIZED V CC RESET THRESHOLDvs. TEMPERATURETEMPERATURE (°C)N O R M A L I Z E D V C C R E S E T T H R E S H O L D6040200-200.9930.9981.0031.0080.988-4080V CC TO RESET OUTPUT DELAYvs. TEMPERATURETEMPERATURE (°C)V C C T O R E S E T O U T P U T D E L A Y (µs )6040200-2033.538.543.548.528.5-4080RESET INPUT TO RESET OUTPUT DELAYvs. TEMPERATURETEMPERATURE (°C)R S T I N T O R E S E T O U T P U T D E L A Y (µs )6040200-2025303520-4080POWER-FAIL INPUT TO POWER-FAIL OUTPUT DELAY vs. TEMPERATURETEMPERATURE (°C)P F I T O P F O D E L A Y (µs )6040200-202939444924-408034Typical Operating Characteristics (continued)(T A = +25°C, unless otherwise noted.)MAX6736–MAX6745Low-Power Dual-/Triple-Voltage SC70 µPSupervisory Circuits_______________________________________________________________________________________7Typical Operating Characteristics (continued)(T A = +25°C, unless otherwise noted.)MR TO RESET OUTPUT DELAYMAX6736-45 toc10100ns/div V MR 2V/divV RESET 2V/divPOWER-FAIL INPUT TO POWER-FAIL OUTPUT DELAYMAX6736-45 toc1110µs/divPFI200mV/divPFO 2V/divV CC TO RESET OUTPUT DELAYMAX6736-45 toc124µs/divV CC200mV/div AC-COUPLEDV RESET 2V/div10020030040050045231678910OUTPUT LOW VOLTAGE vs. SINK CURRENTSINK CURRENT (mA)O U T P U T L O W V O L T A G E (m V )012340.50 1.00 1.500.250.75 1.251.752.00OUTPUT HIGH VOLTAGE vs. SOURCE CURRENTSOURCING CURRENT (mA)O U T P U T H I G H V O L T A G E (V )M A X 6736–M A X 6745Low-Power Dual-/Triple-Voltage SC70 µP Supervisory Circuits 8_______________________________________________________________________________________Pin DescriptionMAX6736–MAX6745Low-Power Dual-/Triple-Voltage SC70 µPSupervisory Circuits9Table 1. Reset Voltage Threshold Suffix Guide for MAX6736/MAX6737/MAX6740/MAX6741/MAX6743/MAX6744Table 2. Reset Voltage Threshold Suffix Guide for MAX6738/MAX6739/MAX6742/MAX6745contact factory for availability.Table 3. V CC Timeout Period Suffix GuideM A X 6736–M A X 6745Low-Power Dual-/Triple-Voltage SC70 µP Supervisory Circuits 10______________________________________________________________________________________Detailed DescriptionSupply VoltagesThe MAX6736–MAX6745 µP supervisory circuits main-tain system integrity by alerting the µP to fault condi-tions. These devices are optimized for systems that monitor two or three supply voltages. The reset output state is guaranteed to remain valid while either V CC 1 or V CC 2 is above 1.2V.Threshold LevelsThe MAX6736/MAX6737/MAX6740/MAX6741/MAX6743/MAX6744 input voltage threshold combinations are indi-cated by a two-letter code in Table 1. The MAX6738/MAX6739/MAX6742/MAX6745 input voltage thresholds are indicated by a one-letter code in Table 2. Contact the factory for the availability of other voltage thresholds.Reset OutputThe MAX6736–MAX6745 provide an active-low reset out-put (RESET ). RESET is asserted when the voltage at either V CC 1 or V CC 2 falls below the voltage threshold level, RSTIN drops below the threshold, or MR is pulled low. Once reset is asserted, it stays low for the reset time-out period. If V CC 1, V CC 2, or RSTIN goes below the reset threshold before the reset timeout period is completed,the internal timer restarts. The MAX6736/MAX6738/MAX6740/MAX6741/MAX6742 have open-drain reset out-puts, while the MAX6737/MAX6739/MAX6743/MAX6744/MAX6745 have push-pull reset outputs (Figure 1).The MAX6740/MAX6741/MAX6742 include a RESET output with a manual reset detect function. The open-drain RESET output has an internal 50k Ωpullup to V CC 1. The RESET output is low while the output is pulled to GND and remains low for at least the manual reset timeout period after the external GND pulldown isFigure 1. Timing DiagramMAX6736–MAX6745Low-Power Dual-/Triple-Voltage SC70 µPSupervisory Circuits______________________________________________________________________________________11released. The manual reset detect function is internally debounced for the t DEB timeout period, so the output can be connected directly to a momentary pushbutton switch, if desired (Figure 2).Manual Reset InputMany microprocessor-based products require manual reset capability, allowing the operator, a test techni-cian, or external logic circuitry to initiate a reset while the monitored supplies remain above their reset thresh-olds. The MAX6736–MAX6739 have a dedicated active-low MR input. The RESET is asserted low while MR is held low and remains asserted for the manual reset timeout period after MR returns high. The MR input has an internal 1.5k Ωpullup resistor to V CC 1and can be left unconnected if not used. MR can be driven with CMOS logic levels, open-drain/open-collector out-puts, or a momentary pushbutton switch to GND to cre-ate a manual reset function.Adjustable Input VoltageThe MAX6738/MAX6739 and MAX6740/MAX6743 pro-vide an additional input to monitor a second or third system voltage. The threshold voltage at RSTIN is typi-cally 488mV. Connect a resistor-divider network to the circuit as shown in Figure 3 to establish an externally controlled threshold voltage, V EXT_TH .V EXT_TH = 0.488V((R1 + R2) / R2)Low leakage current at RSTIN allows the use of large-valued resistors, resulting in reduced power consump-tion of the system.Power-Fail ComparatorPFI is the noninverting input to an auxiliary comparator. A 488mV internal reference (V TH -PFI ) is connected to the inverting input of the comparator. If PFI is less than 488mV, PFO is asserted low. PFO deasserts without a timeout period when PFI rises above the externally set threshold. Common uses for the power-fail comparator include monitoring for low battery conditions or a failing DC-DC converter input voltage (see the Typical Application Circuits ). The asserted PFO output can place a system in a low-power suspend mode or support an orderly system shutdown before monitored V CC voltages drop below the reset thresholds. Connect PFI to an exter-nal resistor-divider network as shown in Figure 4 to set the desired trip threshold. Connect PFI to V CC 1 if unused.Applications InformationInterfacing to the µP with Bidirectional Reset PinsMost microprocessors with bidirectional reset pins can interface directly to open-drain RESET output options.Systems simultaneously requiring a push-pull RESET output and a bidirectional reset interface can be in logic contention. To prevent contention, connect a 4.7k Ωresistor between RESET and the µP ’s reset I/O port as shown in Figure 5.Figure 2. MAX6740/MAX6741/MAX6742 Manual Reset Timing DiagramFigure 3. Monitoring an Additional VoltageM A X 6736–M A X 6745Low-Power Dual-/Triple-Voltage SC70 µP Supervisory Circuits 12______________________________________________________________________________________Adding Hysteresis to the Power-Fail ComparatorThe power-fail comparator has a typical input hystere-sis of 2.5mV. This is sufficient for most applications in which a power-supply line is being monitored through an external voltage-divider. If additional noise margin is desired, connect a resistor between PFO and PFI, asshown in Figure 6. Select the values of R1, R2, and R3such that PFI sees V TH-PFI (488mV) when V EXT falls to its power-fail trip point (V FAIL ) and when V EXT rises to its power-good trip point (V GOOD ). The hysteresis win-dow extends between the specified V FAIL and V GOOD thresholds. R3 adds the additional hysteresis by sink-ing current from the R1/R2 divider network when the PFO output is logic low and sourcing current into the network when PFO is logic high. R3 is typically an order of magnitude greater than R1 or R2.The current through R2 should be at least 1µA to ensure that the 10nA (max) PFI input current does not significant-ly shift the trip points. Therefore, for most applications:R2 < V TH-PFI / 1mA < 0.488V / 1mA < 488k ΩPFO is an open-drain output requiring an externalpullup resistor, R4. Select R4 to be less than 1% of R3.V GOOD = DESIRED V EXT GOOD VOLTAGE THRESHOLD V FAIL = DESIRED V EXT FAIL VOLTAGE THRESHOLD V PU = V PULLUP (FOR OPEN-DRAIN PFO )R2 = 488k Ω(FOR >1µA R2 CURRENT)R3 = (R1 x V PU ) / (V GOOD - V FAIL )R4 ≤0.01 x R3Power Sequencing ApplicationsMany dual-voltage processors/ASICs require specific power-up/power-down sequences for the I/O and core supplies.Power SupplyFigure 6. Adding Hysteresis to Power Fail for Push-Pull PFOMAX6736–MAX6745Low-Power Dual-/Triple-Voltage SC70 µPSupervisory CircuitsFunctional DiagramThe MAX6741/MAX6744 offer a V CC 1 POK (POK1) ideal for V CC 1-to-V CC 2 sequencing. POK1 remains low as long as V CC 1 is below its V TH 1 threshold. When V CC 1exceeds V TH 1 for the POK1 timeout period (t POKP ), the open-drain POK1 output is deasserted. The POK1 output can then enable the V CC 2 power supply (use an external POK1 pullup resistor). RESET is deasserted when both V CC 1 and V CC 2 remain above their selected thresholds for the reset timeout period (t RP ). The POK1 output can be used for I/O before core or core before I/O sequenc-ing, depending on the selected V CC 1/V CC 2 thresholds.See the Typical Application Circuit and Figure 1.Monitoring a Negative VoltageThe power-fail comparator can be used to monitor a negative supply voltage using the circuit shown in Figure 4. When the negative supply is valid, PFO is low.When the negative supply voltage drops, PFO goes high. The circuit ’s accuracy is affected by the PFI threshold tolerance, V CC , R1, and R2.Transient ImmunityThe MAX6736–MAX6745 supervisors are relatively immune to short-duration falling V CC transients (glitch-es). It is usually undesirable to reset the µP when V CC experiences only small glitches. The Typical Operating Characteristics show Maximum V CC 1/V CC 2Transient Duration vs. Reset Threshold Overdrive, for which reset pulses are not generated. The graph shows the maxi-mum pulse width that a falling V CC transient might typi-cally have without causing a reset pulse to be issued.As the amplitude of the transient increases, the maxi-mum allowable pulse width decreases. A 0.1µF bypass capacitor mounted close to the V CC pin provides addi-tional transient immunity.Chip InformationTRANSISTOR COUNT: 249PROCESS: BiCMOSM A X 6736–M A X 6745Low-Power Dual-/Triple-Voltage SC70 µP Supervisory Circuits 14______________________________________________________________________________________Selector Guide (continued)Typical Application CircuitsMAX6736–MAX6745Low-Power Dual-/Triple-Voltage SC70 µPSupervisory Circuits______________________________________________________________________________________15Pin ConfigurationsOrdering Information (continued)M A X 6736–M A X 6745Low-Power Dual-/Triple-Voltage SC70 µP Supervisory Circuits Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.16____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600©2003 Maxim Integrated ProductsPrinted USAis a registered trademark of Maxim Integrated Products.Package Information(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to /packages .)。

MAX038中文资料

MAX038中⽂资料
MAX038 频率⾼、精度好，因此它被称为⾼频精密函数信号发⽣器IC。

在锁相环、压控振荡器、频率合成器、脉宽调制器等电路的设计上，MAX038 都是优选的器件。

其内部电路框图如图1 所⽰。

MAX038 的性能特点：
1)能精密地产⽣三⾓波、锯齿波、矩形波(含⽅波)、正弦波信号。

2)频率范围从0.1Hz～20MHz，最⾼可达40MHz，各种波形的输出幅度均为2V(P-P)。

3)占空⽐调节范围宽，占空⽐和频率均可单独调节，⼆者互不影响，占空⽐最⼤调节范围是10%～90%。

4)波形失真⼩，正弦波失真度⼩于0.75%，占空⽐调节时⾮线性度低于2%。

5)采⽤±5V 双电源供电，允许有5%变化范围，电源电流为80mA，典型功耗400mW，⼯作温度范围为0～70℃。

6)内设2.5V 电压基准，可利⽤该电压设定FADJ、DADJ 的电压值，实现频率微调和占空⽐调节。

MAX038 采⽤DIP-20 封装形式，引脚图如下图所⽰,各管脚的功能如表1 所⽰。

表1MAX038 的管脚功能
注：表中5 个地内部不相连，需外部连接。

MA038极限参数
应⽤电路设计请点击查看: 采⽤MAX038的信号发⽣器电路图具有三种输出波形的函数信号发⽣器电路图(10Hz-10MHz)。

MAX6398中文资料

General DescriptionThe MAX6397/MAX6398 are small, high-voltage overvolt-age protection circuits. These devices disconnect the output load or limit the output voltage during an input overvoltage condition. These devices are ideal for appli-cations that must survive high-voltage transients such as those found in automotive and industrial applications.The MAX6397/MAX6398 monitor the input or output voltages and control an external n-channel MOSFET to isolate or limit the load from overvoltage transient energy.When the monitored input voltage is below the user-adjustable overvoltage threshold, the external n-channel MOSFET is turned on by the GATE output. In this mode,the internal charge pump fully enhances the n-channel MOSFET with a 10V gate-to-source voltage.When the input voltage exceeds the overvoltage thresh-old, the protection can disconnect the load from the input by quickly forcing the GATE output low. In some applications, disconnecting the output from the load is not desirable. In these cases, the protection circuit can be configured to act as a voltage limiter where the GATE output sawtooths to limit the voltage to the load.The MAX6397 also offers an always-on linear regulator that is capable of delivering up to 100mA of output current. This high-voltage linear regulator consumes only 37µA of quiescent current.The regulator is offered with output options of 5V, 3.3V,2.5V, or 1.8V. An open-drain, power-good output (POK)asserts when the regulator output falls below 92.5% or 87.5% of its nominal voltage.The MAX6397/MAX6398 include internal thermal-shut-down protection, disabling the external MOSF ET and linear regulator if the chip reaches overtemperature conditions. The devices operate over a wide 5.5V to 72V supply voltage range, are available in small TDFN packages, and are fully specified from -40°C to +125°C.ApplicationsAutomotive Industrial FireWire ®Notebook Computers Wall Cube Power DevicesFeatures♦5.5V to 72V Wide Supply Voltage Range♦Overvoltage Protection Controllers Allow User to Size External n-Channel MOSFETs ♦Internal Charge-Pump Circuit Ensures MOSFET Gate-to-Source Enhancement for Low R DS(ON)Performance ♦Disconnect or Limit Output from Input During Overvoltage Conditions ♦Adjustable Overvoltage Threshold ♦Thermal-Shutdown Protection♦Always-On, Low-Current (37µA) Linear Regulator Sources Up to 100mA (MAX6397)♦Fully Specified from -40°C to +125°C (T J )♦Small, Thermally Enhanced 3mm x 3mm TDFN PackageMAX6397/MAX6398Overvoltage Protection Switch/LimiterControllers Operate Up to 72V________________________________________________________________Maxim Integrated Products1Pin ConfigurationsOrdering Information19-3668; Rev 3; 1/07For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .Selector Guide and Typical Operating Circuit appear at end of data sheet.FireWire is a registered trademark of Apple Computer, Inc.M A X 6397/M A X 6398Overvoltage Protection Switch/Limiter Controllers Operate Up to 72V 2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGSELECTRICAL CHARACTERISTICS(V= 14V; C = 6000pF, C = 4.7µF, T = T = -40°C to +125°C, unless otherwise noted. Typical values are at T = T = +25°C.)(Note 1)Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional oper-ation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.(All pins referenced to GND, unless otherwise noted.)IN, GATE, OUT............................................................-0.3V to +80V SHDN ..................................................................-0.3V to (IN + 0.3V)GATE to OUT.................................................................-0.3 to +20V SET, REG, POK...........................................................-0.3V to +12V Maximum Current:IN, REG...............................................................................350mA All Remaining Pins...................................................................50mAContinuous Power Dissipation (T A = +70°C)6-Pin TDFN (derate 18.2mW/°C above +70°C).............1455mW 8-Pin TDFN (derate 18.2mW/°C above +70°C).............1455mW Operating Temperature Range (T A )......................-40°C to +125°C Junction Temperature...........................................................+150°C Storage Temperature Range.................................-65°C to +150°C Lead Temperature................................................................+300°CMAX6397/MAX6398Overvoltage Protection Switch/LimiterControllers Operate Up to 72V_______________________________________________________________________________________3ELECTRICAL CHARACTERISTICS (continued)(V IN = 14V; C GATE = 6000pF, C REG = 4.7µF, T A = T J = -40°C to +125°C, unless otherwise noted. Typical values are at T A = T J = +25°C.)(Note 1)Note 1:Specifications to -40°C are guaranteed by design and not production tested.Note 2:The MAX6397/MAX6398 power up with the external FET in off mode (V GATE = GND). The external FET turns on t START after thedevice is powered up and all input conditions are valid.Note 3:For accurate overtemperature shutdown performance, place the device in close thermal contact with the external MOSFET.Note 4:Dropout voltage is defined as V IN - V REG when V REG is 2% below the value of V REG for V IN = V REG (nominal) + 2V.Note 5:Operations beyond the thermal dissipation limit may permanently damage the device.M A X 6397/M A X 6398Overvoltage Protection Switch/Limiter Controllers Operate Up to 72V 4_______________________________________________________________________________________Typical Operating Characteristics(V IN = 14V, C REG = 4.7µF, I REG = 0, unless otherwise noted.)40608010012014016002010304050607080SUPPLY CURRENT vs. INPUT VOLTAGEINPUT VOLTAGE (V)S U P P L Y C U R R E N T (µA )SUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T (µA )1007525500-259010011012013014015016017018080-50125405060708090100110120020406080SUPPLY CURRENT vs. INPUT VOLTAGEINPUT VOLTAGE (V)S U P P L Y CU R R E N T (µA )8010090120110130140-502550-25075100125SUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L YC U R R E N T (µA )20302540354550040206080SHUTDOWN SUPPLY CURRENT vs. INPUT VOLTAGE (MAX6397)INPUT VOLTAGE (V)S U P P L YC U R R E N T (µA )103050700642810121416182020406080SHUTDOWN SUPPLY CURRENTvs. INPUT VOLTAGEINPUT VOLTAGE (V)S U P PL Y C U R R E N T (µA )0642810124121068141618202224GATE-DRIVE VOLTAGE vs. INPUT VOLTAGEINPUT VOLTAGE (V)V G A T E - V O U T (V )4.04.64.44.25.04.85.85.65.45.26.0-50-250255075100125UVLO THRESHOLD vs. TEMPERATUREM A X 6397-98 t o c 08TEMPERATURE (°C)V U V L O (V )SET THRESHOLD vs. TEMPERATUREM A X 6397-98 t o c 09TEMPERATURE (°C)S E T T H R E S H O L D (V )1007525500-251.2041.2081.2121.2161.2201.2241.2281.2321.2361.2401.200-50125MAX6397/MAX6398Overvoltage Protection Switch/LimiterControllers Operate Up to 72V_______________________________________________________________________________________516.016.316.216.116.516.416.916.816.716.617.0-50-25255075100125GATE-TO-OUT CLAMP VOLTAGEvs. TEMPERATUREM A X 6397-98 t o c 10TEMPERATURE (°C)G A T E -T O -O U T C L A M P V O L T A G E (V )00.40.20.80.61.21.01.41.81.62.0040608020100120140160180DROPOUT VOLTAGE vs. REG LOAD CURRENTREG LOAD CURRENT (mA)D R O P O U T V O L T A GE (V )4.905.004.955.105.055.155.20-40-10520-253550658095110125REG OUTPUT VOLTAGEvs. LOAD CURRENT AND TEMPERATURETEMPERATURE (°C)R E G O U T P U T V O L T A G E (V )4.04.64.44.24.85.05.21601204080200240280320360400MAXIMUM REG OUTPUT VOLTAGE vs. LOAD CURRENT AND TEMPERATURELOAD CURRENT (mA)R E G O U T P U T V O L T A G E (V )POWER-SUPPLY REJECTION RATIOvs. FREQUENCYFREQUENCY (Hz)P S R R (d B )1M 100k 10k 1k 100-60-50-40-30-20-100-701010M4ms/divSTARTUP WAVEFORM(R LOAD = 100Ω, C IN = 10µF, C OUT = 10µF)V IN 10V/divMAX6397-98 toc16V GATE 10V/div V OUT 10V/div I OUT200mA/div400µs/divSTARTUP WAVEFORM FROM SHUTDOWN(C IN = 10µF, C OUT = 10µF)V 2V/divV GATE 10V/divV OUT 10V/div I OUT200mA/divR LOAD = 100ΩTypical Operating Characteristics (continued)(V IN = 14V, C REG = 4.7µF, I REG = 0, unless otherwise noted.)GATE-DRIVE VOLTAGE vs. TEMPERATUREM A X 6397-98 t o c 14TEMPERATURE (°C)G A T E -D R I V E V O L T A G E (V )1007525500-2510.45510.46010.46510.47010.47510.48010.48510.49010.49510.50010.450-50125M A X 6397/M A X 6398Overvoltage Protection Switch/Limiter Controllers Operate Up to 72V 6_______________________________________________________________________________________Typical Operating Characteristics (continued)(V IN = 14V, C REG = 4.7µF, I REG = 0, unless otherwise noted.)200µs/divOVERVOLTAGE SWITCH FAULTV IN 20V/divV GATE 20V/div V OUT 20V/div V REG 5V/divV OV = 30V1ms/divVOLTAGE LIMIT FAULTV IN 20V/divV GATE 20V/divV OUT 20V/div V REG 5V/divV OV = 30V400µs/divTRANSIENT RESPONSEV IN 10V/divV REG100mV/divC REG = 10µF I REG = 10mA1ms/divREG LOAD-TRANSIENT RESPONSEV REGAC-COUPLED 500mV/divI REG100mA/divC REG = 10µF1ms/divREGULATOR STARTUP WAVEFORMV IN 10V/divV POK 2V/divV REG 2V/divI REG = 10mA100µs/divREGULATOR POK ASSERTIONV REG 2V/divI REG200mA/div V POK 2V/divI REG = 00V0V0ADetailed Description The MAX6397/MAX6398 are ultra-small, low-current, high-voltage protection circuits for automotive applica-tions that must survive load dump and high-voltage transient conditions. These devices monitor the input/ output voltages and control an external n-channel MOSF ET to isolate the load or to regulate the output voltage from overvoltage transient energy. The con-troller allows system designers to size the external MOSFET to their load current and board size.The MAX6397/MAX6398 drive the MOSF ET’s gate high when the monitored input voltage is below the adjustable overvoltage threshold. An internal charge-pump circuit provides a 5V to 10V gate-to-source drive (see the Typical Operating Characteristics) to ensure low input-to-load voltage drops in normal operating modes. When the input voltage rises above the user-adjusted overvoltage threshold, GATE pulls to OUT, turning off the MOSFET.The MAX6397/MAX6398 are configurable to operate as overvoltage protection switches or as closed-looped volt-age limiters. In overvoltage protection switch mode, theinput voltage is monitored. When an overvoltage condi-tion occurs at IN, GATE pulls low, disconnecting the loadfrom the power source, and then slowly enhances upon removal of the overvoltage condition. In overvoltagelimit mode, the output voltage is monitored and theMAX6397/MAX6398 regulate the source of the external MOSFET at the adjusted overvoltage threshold, allowing devices within the system to continue operating during an overvoltage condition.The MAX6397/MAX6398 undervoltage lockout (UVLO) function disables the devices as long as the input remains below the 5V (typ) UVLO turn-on threshold. TheMAX6397/MAX6398 have an active-low SHDN input toturn off the external MOSFET, disconnecting the load and reducing power consumption. After power is applied and SHDN is driven above its logic-high voltage, there is a100µs delay before GATE enhancement commences.MAX6397/MAX6398Overvoltage Protection Switch/LimiterControllers Operate Up to 72V _______________________________________________________________________________________7M A X 6397/M A X 6398The MAX6397 integrates a high-input-voltage, low-qui-escent-current linear regulator in addition to an over-voltage protector circuit. The linear regulator remains enabled at all times to power low-current “always-on”applications (independent of the state of the external MOSF ET). The regulator is offered with several stan-dard output voltage options (5V, 3.3V, 2.5V, or 1.8V).An open-drain power-good output notifies the system if the regulator output falls to 92.5% or 87.5% of its nomi-nal voltage. The MAX6397’s REG output operates inde-pendently of the SHDN logic input.The MAX6397/MAX6398 include internal thermal-shut-down protection, disabling the external MOSF ET and linear regulator if the chip reaches overtemperature conditions.Linear Regulator (MAX6397 Only)The MAX6397 is available with 5.0V, 3.3V, 2.5V, and 1.8V factory-set output voltages. Each regulator sources up to 100mA and includes a current limit of 230mA. The linear regulator operates in an always-on condition regardless of the SHDN logic. For fully specified operation, V IN must be greater than 6.5V for the MAX6397L/M (5V regulator output). The actual output current may be limited by the operating condition and package power dissipation.Power-OK OutputPOK is an open-drain output that goes low when REG falls to 92.5% or 87.5% (see the Selector Guide ) of its nominal output voltage. To obtain a logic-level output,connect a pullup resistor from POK to REG or another system voltage. Use a resistor in the 100k Ωrange to minimize current consumption. POK provides a valid logic-output level down to V IN = 1.5V.GATE VoltageThe MAX6397/MAX6398 use a high-efficiency charge pump to generate the GATE voltage. Upon V IN exceed-ing the 5V (typ) UVLO threshold, GATE enhances 10V above IN (for V IN ≥14V) with a 75µA pullup current. An overvoltage condition occurs when the voltage at SET pulls above its 1.215V threshold. When the threshold is crossed, GATE falls to OUT within 100ns with a 100mA (typ) pulldown current. The MAX6397/MAX6398 include an internal clamp to OUT that ensures GATE is limited to 18V (max) above OUT to prevent gate-to-source damage to the external FET.The GATE cycle during overvoltage limit and overvolt-age switch modes are quite similar but have distinct characteristics. In overvoltage switch mode (Figure 2a),GATE is enhanced to V IN + 10V while the monitored IN voltage remains below the overvoltage fault threshold (SET < 1.215V). When an overvoltage fault occurs (SET ≥1.215V), GATE is pulled one diode below OUT, turn-ing off the external F ET and disconnecting the load from the input. GATE remains low (FET off) as long as V IN is above the overvoltage fault threshold. As V IN falls back below the overvoltage fault threshold (-5% hys-teresis) GATE is again enhanced to V IN + 10V.In overvoltage limit mode (Figure 2b), GATE is enhanced to V IN + 10V. While the monitored OUT voltage remains below the overvoltage fault threshold (SET < 1.215V).When an overvoltage fault occurs (SET ≥1.215V),GATE is pulled low one diode drop below OUT until OUT drops 5% below the overvoltage fault threshold.GATE is then turned back on until OUT again reaches the overvoltage fault threshold and GATE is again turned off.Overvoltage Protection Switch/Limiter Controllers Operate Up to 72V 8_______________________________________________________________________________________GATE cycles on-off-on-off-on in a sawtooth waveform until OUT remains below the overvoltage fault threshold and GATE remains constantly on (V IN + 10V). The over-voltage limiter’s sawtooth GATE output operates the MOSFET in a switched-linear mode while the input volt-age remains above the overvoltage fault threshold. The sawtooth frequency depends on the load capacitance,load current, and MOSFET turn-on time (GATE charge current and GATE capacitance).GATE goes high when the following startup conditions are met: V IN is above the UVLO threshold, SHDN is high, an overvoltage fault is not present and the device is not in thermal shutdown.Overvoltage MonitoringWhen operating in overvoltage mode, the MAX6397/MAX6398 feedback path (F igure 3) consists of IN,SET’s internal comparator, the internal gate charge pump, and the external n-channel MOSFET resulting in a switch-on/off function. When the programmed over-voltage threshold is tripped, the internal fast compara-tor turns off the external MOSFET, pulling GATE to OUT within t OV and disconnecting the power source from the load. When IN decreases below the adjusted over-voltage threshold, the MAX6397/MAX6398 slowly enhance GATE above OUT, reconnecting the load to the power source.Overvoltage LimiterWhen operating in overvoltage limiter mode, the MAX6397/MAX6398 feedback path (F igure 4) consists of OUT, SET’s internal comparator, the internal gate charge pump and the external n-channel MOSF ET,which results in the external MOSF ET operating as a voltage regulator.During normal operation, GATE is enhanced 10V above OUT. The external MOSFET source voltage is monitored through a resistor-divider between OUT and SET. When OUT rises above the adjusted overvoltage threshold, an internal comparator sinks the charge-pump current, dis-charging the external GATE, regulating OUT at the set overvoltage threshold. OUT remains active during the overvoltage transients and the MOSFET continues to con-duct during the overvoltage event, operating in switched-linear mode.MAX6397/MAX6398Overvoltage Protection Switch/LimiterControllers Operate Up to 72V_______________________________________________________________________________________9V GATE 10V/divV OUT 10V/divV IN 10V/div10ms/divV GATE 10V/divV OUT 10V/divV IN 10V/div4ms/divM A X 6397/M A X 6398As the transient begins decreasing, OUT fall time will depend on the MOSF ET’s GATE charge, the internal charge-pump current, the output load, and the tank capacitor at OUT.For fast-rising transients and very large-sized MOSFETs,add an additional external bypass capacitor from GATE to GND to reduce the effect of the fast-rising voltages at IN. The external capacitor acts as a voltage-divider working against the MOSF ETs’ drain-to-gate capaci-tance. For a 6000pF C gd , a 0.1µF capacitor at GATE will reduce the impact of the fast-rising V IN input.Caution must be exercised when operating the MAX6397/MAX6398 in voltage-limiting mode for long durations. If the V IN is a DC voltage greater than the MOSFET’s maximum gate voltage, the FET will dissipate power continuously. To prevent damage to the external MOSFET, proper heatsinking should be implemented.Applications InformationLoad DumpMost automotive applications run off a multicell, 12V lead-acid battery with a nominal voltage that swings between 9V and 16V (depending on load current,charging status, temperature, battery age, etc.). The battery voltage is distributed throughout the automobile and is locally regulated down to voltages required by the different system modules. Load dump occurs when the alternator is charging the battery and the battery becomes disconnected. Power in the alternator (essen-tially an inductor) flows into the distributed power sys-tem and elevates the voltage seen at each module. The voltage spikes have rise times typically greater than 5ms and decays within several hundred milliseconds but can extend out to 1s or more depending on thecharacteristics of the charging system (F igure 5).These transients are capable of destroying semicon-ductors on the first ‘fault event.’Setting Overvoltage ThresholdsSET provides an accurate means to set the overvoltage level for the MAX6397/MAX6398. Use a resistor-divider to set the desired overvoltage condition (Figure 6). SET has a rising 1.215V threshold with a 5% falling hysteresis.Begin by selecting the total end-to-end resistance,R TOTAL = R1 + R2. Choose R TOTAL to yield a total cur-rent equivalent to a minimum 100 x I SET (SET’s input bias current) at the desired overvoltage threshold.For example:With an overvoltage threshold set to 20V:R TOTAL < 20V/(100 x I SET )where I SET is SET’s 50nA input bias current.R TOTAL < 4M ΩUse the following formula to calculate R2:where V TH is the 1.215V SET rising threshold and V OV is the overvoltage threshold.R2 = 243k Ω, use a 240k Ωstandard resistor.R TOTAL = R2 + R1, where R1 = 3.76M Ω.Use a 3.79M Ωstandard resistor.A lower value for total resistance dissipates morepower but provides slightly better accuracy.Overvoltage Protection Switch/Limiter Controllers Operate Up to 72V 10______________________________________________________________________________________Reverse-Battery ProtectionUse a diode or p-channel MOSF ET to protect the MAX6397/MAX6398 during a reverse-battery insertion (Figures 7a, 7b). Low p-channel MOSFET on-resistance of 30m Ωor less yields a forward-voltage drop of only a few millivolts (versus hundreds of millivolts for a diode,Figure 7a) thus improving efficiency.Connecting a positive battery voltage to the drain of Q1(F igure 7b) produces forward bias in its body diode,which clamps the source voltage one diode drop below the drain voltage. When the source voltage exceeds Q1’s threshold voltage, Q1 turns on. Once the F ET is on, the battery is fully connected to the system and can deliver power to the device and the load.An incorrectly inserted battery reverse-biases the F ET’s body diode. The gate remains at the ground potential.The FET remains off and disconnects the reversed bat-tery from the system. The zener diode and resistor com-bination prevent damage to the p-channel MOSF ET during an overvoltage condition.MAX6397/MAX6398Overvoltage Protection Switch/LimiterControllers Operate Up to 72V______________________________________________________________________________________11M A X 6397/M A X 6398REG Capacitor Selection for StabilityFor stable operation over the full temperature range and with load currents up to 100mA, use ceramic capacitor values greater than 4.7µF. Large output capacitors help reduce noise, improve load-transient response, and power-supply rejection at REG. Note that some ceramic dielectrics exhibit large capacitance and ESR variation with temperature. At lower temperatures, it may be nec-essary to increase capacitance.Under normal conditions, use a 10µF capacitor at rger input capacitor values and lower ESR provide bet-ter supply-noise rejection and line-transient response.Inrush/Slew-Rate ControlInrush current control can be implemented by placing a capacitor at GATE (F igure 8) to slowly ramp up the GATE, thus limiting the inrush current and controlling GATE’s slew rate during initial turn-on. The inrush cur-rent can be approximated using the following formula:where I GATE is GATE’s 75µA sourcing current, I LOAD is the load current at startup, and C OUT is the output capacitor.Input Transients ClampingWhen the external MOSFET is turned off during an over-voltage occurrence, stray inductance in the power path may cause voltage ringing exceeding the MAX6397/MAX6398 absolute maximum input (IN) supply rating.The following techniques are recommended to reduce the effect of transients:•Minimize stray inductance in the power path usingwide traces, and minimize loop area including the power traces and the return ground path.•Add a zener diode or transient voltage suppressor(TVS) rated below the IN absolute maximum rating (Figure 9).Add a resistor in series with IN to limit transient currentgoing into the input for the MAX6398 only.Overvoltage Protection Switch/Limiter Controllers Operate Up to 72V 12______________________________________________________________________________________Figure 8. MAX6397/MAX6398 Controlling GATE Inrush CurrentFigure 9. Protecting the MAX6397/MAX6398 Input from High-Voltage TransientsMOSFET SelectionSelect external MOSF ETs according to the application current level. The MOSF ET’s on-resistance (R DS(ON))should be chosen low enough to have minimum voltage drop at full load to limit the MOSFET power dissipation.Determine the device power rating to accommodate an overvoltage fault when operating the MAX6397/MAX6398 in overvoltage limit mode.During normal operation, the external MOSFETs dissipate little power. The power dissipated in normal operation is:P Q1 = I LOAD 2x R DS(ON).The most power dissipation will occur during a pro-longed overvoltage event when operating the MAX6397/MAX6398 in voltage limiter mode, resulting in high power dissipated in Q1 (F igure 10) where the power dissipated across Q1 is:P Q1= V Q1x I LOADwhere V Q1is the voltage across the MOSF ET’s drain and source.Thermal ShutdownThe MAX6397/MAX6398 thermal-shutdown feature shuts off the linear regulator output, REG, and GATE if it exceeds the maximum allowable thermal dissipation.Thermal shutdown also monitors the PC board tempera-ture of the external nF ET when the devices sit on thesame thermal island. Good thermal contact between the MAX6397/MAX6398 and the external nF ET is essential for the thermal-shutdown feature to operate effectively.Place the nFET as close as possible to OUT.When the junction temperature exceeds T J = +150°C,the thermal sensor signals the shutdown logic, turning off REG’s internal pass transistor and the GATE output,allowing the device to cool. The thermal sensor turns the pass transistor and GATE on again after the IC’s junction temperature cools by 20°C. Thermal-overload protection is designed to protect the MAX6397/MAX6398 and the external MOSFET in the event of cur-rent-limit fault conditions. For continuous operation, do not exceed the absolute maximum junction-tempera-ture rating of T J = +150°C.Thermal ShutdownOvervoltage Limiter ModeWhen operating the MAX6397/MAX6398 in overvoltage limit mode for a prolonged period of time, a thermal shutdown is possible due to device self-heating. The thermal shutdown is dependent on a number of differ-ent factors:•The device’s ambient temperature (T A )•The output capacitor (C OUT )•The output load current (I OUT )•The overvoltage threshold limit (V OV )•The overvoltage waveform period (t OVP )•The power dissipated across the package (P DISS )MAX6397/MAX6398Overvoltage Protection Switch/LimiterControllers Operate Up to 72V______________________________________________________________________________________13M A X 6397/M A X 6398When OUT exceeds the adjusted overvoltage threshold,an internal GATE pulldown current is enabled until OUT drops by 5%. The capacitance at OUT is discharged by the internal current sink and the external OUT load cur-rent. The discharge time (∆t1) is approximately:where V OV is the adjusted overvoltage threshold, I OUT is the external load current and I GATEPD is the GATE’s internal 100mA (typ) pulldown current.When OUT falls 5% below the overvoltage threshold point, the internal current sink is disabled and the MAX6397/MAX6398’s internal charge pump begins recharging the external GATE voltage. The OUT volt-age continues to drop due to the external OUT load current until the MOSF ET gate is recharged. The time needed to recharge GATE and re-enhance the external nFET is approximately:where C ISS is the MOSFET’s input capacitance, V GS(TH)is the MOSFET’s gate-to-source threshold voltage, V F is the internal clamp diode forward voltage (V F = 1.5V typ),and I GATE is the MAX6397/MAX6398 charge-pump cur-rent (75µA typ).During ∆t2, C OUT loses charge through the output load.The voltage across C OUT (∆V2) decreases until the MOSF ET reaches its V GS(TH) threshold and can be approximated using the following formula:Once the MOSFET V GS (TH ) is obtained, the slope of the output voltage rise is determined by the MOSF ET Q G charge through the internal charge pump with respect to the drain potential. The time for the OUT voltage to rise again to the overvoltage threshold can be approxi-mated using the following formula:where ∆V OUT = ( V OV x 0.05) + ∆V2.The total period of the overvoltage waveform can be summed up as follows:t OVP = ∆t1 + ∆t2 + ∆t3The MAX6397/MAX6398 dissipate the most power dur-ing an overvoltage event when I OUT = 0 (C OUT is dis-charged only by the internal current sink). The maximum power dissipation can be approximated using the follow-ing equation:The die temperature (T J ) increase is related to θJC (8.3°C/W and 8.5°C/W for the MAX6397 and MAX6398,respectively) of the package when mounted correctly with a strong thermal contact to the circuit board. The MAX6397/MAX6398 thermal shutdown is governed by the equation:T J = T A + P DISS x (θJC + θCA) < 170°C (typical thermal-shutdown temperature)For the MAX6397, the power dissipation of the internal linear regulator must be added to the overvoltage pro-tection circuit power dissipation to calculate the die temperature. The linear regulator power dissipation is calculated using the following equation:P REG = (V IN – V REG ) (I REG )F or example, using an IRF R3410 100V n-channel MOSF ET, F igure 12 illustrates the junction temperature vs. output capacitor with I OUT = 0, T A = +125°C, V OV < 16V,V F = 1.5V, I GATE = 75mA, and I GATEPD =100mA. Figure 12 shows the relationship between output capacitance versus die temperature for the conditionslisted above.Overvoltage Protection Switch/Limiter Controllers Operate Up to 72V 14______________________________________________________________________________________。

MAX807中文资料

MAX807L/M/NFull-Featured µP Supervisory Circuit with±1.5% Reset Accuracy________________________________________________________________Maxim Integrated Products1Call toll free 1-800-998-8800 for free samples or literature.19-0433; Rev 0; 9/95_______________General DescriptionThe MAX807 microprocessor (µP) supervisory circuit reduces the complexity and number of components needed to monitor power-supply and battery-control func-tions in µP systems. A 70µA supply current makes the MAX807 ideal for use in portable equipment, while a 2ns chip-enable propagation delay and 250mA output current capability (20mA in battery-backup mode) make it suit-able for larger, higher-performance equipment.The MAX807 comes in 16-pin DIP and SO packages, and provides the following functions:1)output is asserted dur-ing power-up, power-down, and brownout conditions,and is guaranteed to be in the correct state for V CC down to 1V.2)Active-high RESET output.3)Manual-reset input.4)Two-stage power-fail warning. A separate low-line comparator compares V CC to a threshold 52mV above the reset threshold. This low-line comparator is more accurate than those in previous µP supervisors.5) Backup-battery switchover for CMOS RAM, real-time clocks, µPs, or other low-power logic.6)Write protection of CMOS RAM or EEPROM.7) 2.275V threshold detector—provides for power-fail warning and low-battery detection, or monitors a power supply other than +5V.8)BATT OK status flag indicates that the backup-battery voltage is above 2.275V.9)Watchdog-fault output—asserted if the watchdog input has not been toggled within a preset timeout period.________________________ApplicationsComputers ControllersIntelligent Instruments Critical µP Power Monitoring Portable/Battery-Powered Equipment____________________________Featureso Precision 4.675V (MAX807L) or 4.425V (MAX807M), or 4.575V (MAX807N) Voltage Monitoring o 200ms Power OK / Reset Time Delay o and RESET Outputs o Independent Watchdog Timer o 1µA Standby Currento Power Switching:250mA in V CC Mode20mA in Battery-Backup Modeo On-Board Gating of Chip-Enable Signals:2ns CE Gate Propagation Delay o MaxCap™and SuperCap™Compatible o Voltage Monitor for Power-Fail o Backup-Battery Monitoro Guaranteed RESET Valid to V CC = 1Vo ±1.5% Low-line Threshold Accuracy 52mV above Reset Threshold__________________Pin ConfigurationOrdering Information and Typical Operating Circuit appear at end of data sheet.SuperCap is a trademark of Baknor Industries. MaxCap is a trademark of The Carborundum Corp.M A X 807L /M /NFull-Featured µP Supervisory Circuit with ±1.5% Reset Accuracy 2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGSELECTRICAL CHARACTERISTICS(V CC = 4.60V to 5.5V for the MAX807L, V CC = 4.50V to 5.5V for the MAX807N, V CC = 4.35V to 5.5V for the MAX807M,V= 2.8V, V = 0V, T = T to T . Typical values are tested with V = 5V and T = +25°C, unless otherwise noted.)Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.Input Voltages (with respect to GND)V CC ..........................................................................-0.3V to 6V V BATT .......................................................................-0.3V to 6V All Other Inputs......................................-0.3V to (V OUT + 0.3V)Input CurrentV CC Peak ...........................................................................1.0A V CC Continuous.............................................................500mA I BATT Peak......................................................................250mA I BATT Continuous .............................................................50mA GND.................................................................................50mA All Other Inputs................................................................50mAContinuous Power Dissipation (T A = +70°C)Plastic DIP (derate 10.53mW/°C above +70°C)...........842mW Wide SO (derate 9.52mW/°C above +70°C).................762mW CERDIP (derate 10.00mW/°C above +70°C)................800mW Operating Temperature RangesMAX807_C_E.......................................................0°C to +70°C MAX807_E_E....................................................-40°C to +85°C MAX807_MJE .................................................-55°C to +125°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering, 10sec).............................+300°CMAX807L/M/NFull-Featured µP Supervisory Circuit with±1.5% Reset Accuracy_______________________________________________________________________________________3ELECTRICAL CHARACTERISTICS (continued)(V CC = 4.60V to 5.5V for the MAX807L, V CC = 4.50V to 5.5V for the MAX807N, V CC = 4.35V to 5.5V for the MAX807M,V = 2.8V, V = 0V, T = T to T . Typical values are tested with V = 5V and T = +25°C, unless otherwise noted.)M A X 807L /M /NFull-Featured µP Supervisory Circuit with ±1.5% Reset Accuracy 4_______________________________________________________________________________________Note 1:Either V CC or V BATT can go to 0V, if the other is greater than 2.0V.Note 2:The supply current drawn by the MAX807 from the battery (excluding I OUT ) typically goes to 15µA when (V BATT - 0.1V)< V CC < V BATT . In most applications, this is a brief period as V CC falls through this region (see Typical Operating Characteristics ).Note 3:“+”= battery discharging current, “-”= battery charging current.Note 4:WDI is internally connected to a voltage divider between V CC and GND. If unconnected, WDI is driven to 1.8V (typical),disabling the watchdog function.Note 5:Overdrive (V OD ) is measured from center of hysteresis band.Note 6:The chip-enable resistance is tested with V CE IN = V CC /2, and I CE IN = 1mA.Note 7:The chip-enable propagation delay is measured from the 50% point at CE IN to the 50% point at CE OUT.ELECTRICAL CHARACTERISTICS (continued)(V CC = 4.60V to 5.5V for the MAX807L, V CC = 4.50V to 5.5V for the MAX807N, V CC = 4.35V to 5.5V for the MAX807M,V BATT = 2.8V, V PFI = 0V, T A = T MIN to T MAX . Typical values are tested with V CC = 5V and T A = +25°C, unless otherwise noted.)MAX807L/M/NFull-Featured µP Supervisory Circuit with±1.5% Reset Accuracy_______________________________________________________________________________________58060-60-2060140V CC SUPPLY CURRENT vs. TEMPERATURE(NORMAL OPERATING MODE)6476M A X 807-01TEMPERATURE (°C)V C C S U P P L Y C U R R E N T (µA )20100-404012008072686266787470 3.02.52.01.51.00.50-60-2060140BATTERY SUPPLY CURRENT vs.TEMPERATURE (BATTERY-BACKUP MODE)M A X 807-02TEMPERATURE (°C)B A T T E R Y S U P P L Y C U R R E N T (µA )20100-40401200806543210-60-2060140CHIP-ENABLE PROPAGATION DELAYvs. TEMPERATUREM A X 807-03TEMPERATURE (°C)P R O P A G A T I O N D E L A Y (n s )20100-4040120080305-60-2060140BATT-to-OUT ON-RESISTANCEvs. TEMPERATURE1025TEMPERATURE (°C)B A T T -t o -O U T O N -R E S I S T A NC E (Ω)20100-404012008020154.704.654.604.554.504.454.40-60-2060140RESET THRESHOLD vs. TEMPERATURETEMPERATURE (°C)R E S E T T H R E S H O L D (V )20100-4040120080 1.61.51.41.31.21.11.00.90.80.7-60-2060140V CC -to-OUT ON-RESISTANCEvs. TEMPERATURETEMPERATURE (°C)V C C -t o -O U T O N -R E S I S T A N C E (Ω)20100-4040120080 2.3402.3202.3002.2802.2602.2402.2202.200-60-2060140PFI THRESHOLDvs. TEMPERATURE (V PFI FALLING)M A X 807-06TEMPERATURE (°C)P F I T H R E S H O L D (V )20100-4040120080280260240220200180160140-60-2060140RESET TIMEOUT PERIOD vs. TEMPERATURE (V CC RISING)M A X 807-08TEMPERATURE (°C)R E S E T T I M E O U T P E R I O D (m s )20100-404012008001020304050607080-60-2060140LOW LINE -to-RESET THRESHOLD vs. TEMPERATURE (V CC FALLING)M A X 807-09TEMPERATURE (°C)L O W L I N E -t o -R E S E T T H R E S H O L D (m V )20100-4040120080__________________________________________Typical Operating Characteristics(V CC = 5V, V BATT = 2.8V, PFI = 0V, no load, T A = +25°C, unless otherwise noted.)M A X 807L /M /NFull-Featured µP Supervisory Circuit with ±1.5% Reset Accuracy 6___________________________________________________________________________________________________________________Typical Operating Characteristics (continued)(V CC = 5V, V BATT = 2.8V, PFI = 0V, no load, T A = +25°C, unless otherwise noted.)4.754.804.704.654.604.554.504.45 4.40-60-2060140LOW LINE THRESHOLDvs. TEMPERATURE (V CC RISING)TEMPERATURE (°C)L O W L I N E T H R E S H O L D (V )20100-40401200800510152025303540-60-2060140LOW LINE COMPARATOR PROPAGATION DELAY vs. TEMPERATURE (V CC FALLING)TEMPERATURE (°C)L O W L I N E C O M P A R A T O R P R O P . D E L A Y (µs )20100-40401200800510152025303540-60-2060140RESET COMPARATOR PROPAGATION DELAY vs. TEMPERATURE (V CC FALLING)TEMPERATURE (°C)R E S E T C O M P A R A T O R P R O P . D E L A Y (µs )20100-404012008002468101214162.52.62.72.82.93.0BATTERY CURRENT vs. INPUT SUPPLY VOLTAGEM A X 807-13V CC (V)B A T T E R YC U R R E N T (µA )10001001011100101000V CC -to-OUT vs. OUTPUT CURRENTI OUT (mA)V C C -V O U T (m V )50Ω DRIVER2468050100CHIP-ENABLE PROPAGATION DELAY vs. CE OUT LOAD CAPACITANCEM A X 807-14C LOAD (pF)P R O P A G A T I O N D E L A Y (n s)100010010110100BATT-to-OUT vs. OUTPUT CURRENTI OUT (mA)B A T T -t o -O U T (m V )10001001011100101000MAXIMUM TRANSIENT DURATION vs. RESET COMPARATOR OVERDRIVERESET COMPARATOR OVERDRIVE (mV)M A X I M U M T R A N S I E N T D U R A T I O N (µs )MAX807L/M/NFull-Featured µP Supervisory Circuit with±1.5% Reset Accuracy_______________________________________________________________________________________7______________________________________________________________Pin Description_______________Detailed DescriptionThe MAX807 microprocessor (µP) supervisory circuit provides power-supply monitoring, backup-battery switchover, and program execution watchdog functions in µP systems (Figure 1). Use of BiCMOS technology results in an improved 1.5% reset-threshold precision,while keeping supply currents typically below 70µA.The MAX807 is intended for battery-powered applica-tions that require high reset-threshold precision, allow-ing a wide power-supply operating range while preventing the system from operating below its speci-fied voltage range.RESET and RESET OutputsThe MAX807’s RESET output ensures that the µP pow-ers up in a known state, and prevents code execution errors during power-down and brownout conditions. It accomplishes this by resetting the µP, terminating pro-gram execution when V CC dips below the reset thresh-old or MR is pulled low. Each time RESET is asserted it stays low for the 200ms reset timeout period, which is set by an internal timer to ensure the µP has adequate time to return to an initial state. Any time V CC goes below the reset threshold before the reset timeout peri-od is completed, the internal timer restarts. The watch-dog timer can also initiate a reset if WDO is connected to MR. See the Watchdog Input section.M A X 807L /M /NFull-Featured µP Supervisory Circuit with ±1.5% Reset Accuracy 8_______________________________________________________________________________________Figure 1. Block DiagramMAX807L/M/NFull-Featured µP Supervisory Circuit with±1.5% Reset Accuracy_______________________________________________________________________________________9output is active low and implemented with a strong pull-down/relatively weak pull-up structure. It is guaranteed to be a logic low for 0V < V CC < V RST , pro-vided V BATT is greater than 2V. Without a backup bat-is guaranteed valid for V CC ≥1. It typically sinks 3.2mA at 0.1V saturation voltage in its active state.The RESET output is the inverse of the RESET output; it both sources and sinks current and cannot be wire-OR connected.Manual Reset InputMany µP-based products require manual-reset capabil-ity to allow an operator or test technician to initiate a tion of a reset in response to a logic low from a switch,WDO, or external circuitry. Reset remains asserted while MR is low, and for 200ms after MR returns high. MR has an internal 50µA to 200µA pull-up current, so it can be driven with TTL or CMOS-logic levels, or with open-drain/collector outputs. Connect a normally open momentary switch from MR to GND to create a manual-reset function;is dri-ven from long cables or if the device is used in a noisy to ground to provide additional noise immunity. As shown in Figure 3, diode-ORed connections can be used to allow manual resets from multiple sources. Figure 4shows the reset timing.Watchdog InputThe watchdog circuit monitors the µP’s activity. If the µP does not toggle the watchdog input (WDI) within 1.6sec, WDO goes low. The internal 1.6sec timer is returns high when reset is asserted or when a transition (low-to-high or high-to-low) occurs is high. As long as reset is assert-ed, the timer remains cleared and does not count. As soon as reset is released, the timer starts counting (Figure 5). Supply current is typically reduced by 10µA when WDI is at a valid logic level.Figure 2a. Timing Diagram, V CC Rising Figure 2b. Timing Diagram, V CC FallingM A X 807L /M /NFull-Featured µP Supervisory Circuit with ±1.5% Reset Accuracy 10______________________________________________________________________________________Watchdog OutputWDO remains high if there is a transition or pulse at WDI during the watchdog timeout period. WDO goes low if no transition occurs at WDI during the watchdog timeout period. The watchdog function is disabled and WDO is a logic high when V CC is below the reset threshold or WDI is an open circuit. To generate a sys-tem reset on every watchdog fault, simply diode-OR connect WDO to MR (Figure 6). When a watchdog fault occurs in this mode, WDO goes low, which pulls MR low, causing a reset pulse to be issued. As soon as reset is asserted, the watchdog timer clears and WDO returns high. With WDO connected to MR, a continuous high or low on WDI will cause 200ms reset pulses to be issued every 1.6sec.Chip-Enable Signal GatingThe MAX807 provides internal gating of chip-enable (CE) signals to prevent erroneous data from corrupting the CMOS RAM in the event of a power failure. During normal operation, the CE gate is enabled and passes all CE transitions. When reset is asserted, this path becomes disabled, preventing erroneous data from corrupting the CMOS RAM. The MAX807 uses a series transmission gate from the Chip-Enable Input (CE IN) to the Chip-Enable Output (CE OUT) (Figure 1).The 8ns max chip-enable propagation from CE IN to CE OUT enables the MAX807 to be used with most µPs.Chip-Enable InputCE IN is high impedance (disabled mode) while RESET is asserted. During a power-down sequence when V CC passes the reset threshold, the CE transmission gate disables and CE IN becomes high impedance 28µs after reset is asserted (Figure 7). During a power-up sequence, CE IN remains high impedance (regardless of CE IN activity) until reset is deasserted following the reset-timeout period.In the high-impedance mode, the leakage currents into this input are ±1µA max over temperature. In the low-impedance mode, the impedance of CE IN appears as a 75Ωresistor in series with the load at CE OUT.The propagation delay through the CE transmission gate depends on both the source impedance of the drive to CE IN and the capacitive loading on CE OUTFigure 4. Manual-Reset Timing DiagramFigure 5. Watchdog Timing Relationship Figure 6. Generating a Reset on Each Watchdog FaultMAX807L/M/NFull-Featured µP Supervisory Circuit with±1.5% Reset Accuracy______________________________________________________________________________________11Load Capacitance graph in the Typical Operating Characteristics ). The CE propagation delay is produc-tion tested from the 50% point on CE IN to the 50%point on CE OUT using a 50Ωdriver and 50pF of load capacitance (Figure 8). For minimum propagation delay, minimize the capacitive load at CE OUT and use a low output-impedance driver.Chip-Enable OutputIn the enabled mode, the impedance of CE OUT is equiv-alent to 75Ωin series with the source driving CE IN. In the disabled mode, the 75Ωtransmission gate is off and CE OUT is actively pulled to the higher of V CC or V BATT . This source turns off when the transmission gate is enabled.Low-Line ComparatorThe low-line comparator monitors V CC with a threshold voltage typically 52mV above the reset threshold, with 13mV of hysteresis. Use LOW LINE to provide a non-maskable interrupt (NMI) to the µP when power begins to fall, to initiate an orderly software shutdown routine.In most battery-operated portable systems, reserve energy in the battery provides ample time to complete the shutdown routine once the low-line warning is encountered, and before reset asserts. If the system must contend with a more rapid V CC fall time—such as when the main battery is disconnected, a DC-DC con-verter shuts down, or a high-side switch is opened dur-ing normal operation—use capacitance on the V CC line to provide time to execute the shutdown routine (Figure 9). First calculate the worst-case time required for the system to perform its shutdown routine. Then, with theand the minimum low-line to reset threshold (V LR(min)),calculate the amount of capacitance required to allow the shutdown routine to complete before reset is asserted:C HOLD = (I LOAD x t SHDN ) / V LR (min)where t SHDN is the time required for the system to com-plete the shutdown routine, and includes the V CC to low-line propagation delay; and where I LOAD is the cur-rent being drained from the capacitor, V LR is the low-line to reset threshold.Figure 8. CE Propagation Delay Test CircuitM A X 807L /M /NPower-Fail ComparatorPFI is the noninverting input to an uncommitted com-parator. If PFI is less than V PFT (2.265V), PFO goes low.The power-fail comparator is intended to monitor the preregulated input of the power supply, providing an early power-fail warning so software can conduct an orderly shutdown. It can also be used to monitor sup-plies other than 5V. Set the power-fail threshold with a resistor divider, as shown in Figure 10.Power-Fail InputPFI is the input to the power-fail comparator. The typical comparator delay is 14µs from V IL to V OL (power failing),and 32µs from V IH to V OH (power being restored). If unused, connect this input to ground.Power-Fail OutputThe Power-Fail Output (PFO) goes low when PFI goes below V PFT . It typically sinks 3.2mA with a saturation voltage of 0.1V. With PFI above V PFT , PFO is actively pulled to V CC . Connecting PFI through a voltage divider to a preregulated supply allows PFO to generate an NMI as the preregulated power begins to fall (Figure 11b). If the preregulated supply is inaccessible, use LOW LINE LINE threshold is typically 52mV above the reset threshold (see Low-Line Comparator section).Full-Featured µP Supervisory Circuit with ±1.5% Reset Accuracy 12______________________________________________________________________________________Figure 10. Using the Power-Fail Comparator to Monitor an Additional Power Supply: a) V IN is Negative, b) V IN is PositiveFigure 11. a) If the preregulated supply is inaccessible, LOW LINE generates the NMI for the µP. b) Use PFO to generate the µP NMI if the preregulated supply is accessible.Battery-Backup ModeBattery backup preserves the contents of RAM in the event of a brownout or power failure. With a backup battery installed at BATT, the MAX807 automatically switches RAM to backup power when V CC falls. Two conditions are required for switchover to battery-back-up mode: 1) V CC must be below the reset threshold; 2)V CC must be below V BATT . Table 1 lists the status of inputs and outputs during battery-backup mode.Backup-Battery InputThe BATT input is similar to V CC , except the PMOS switch is much smaller. This input is designed to con-duct up to 20mA to OUT during battery backup. The on-resistance of the PMOS switch is approximately 13Ω. Figure 12 shows the two series pass elements between the BATT input and OUT that facilitates UL approval. V BATT can exceed V CC during normal opera-tion without causing a reset.Output Supply VoltageThe output supply (OUT) transfers power from V CC or BATT to the µP, RAM, and other external circuitry. At the maximum source current of 250mA, V OUT will typi-cally be 260mV below V CC . Decouple this terminal with a 0.1µF capacitor.BATT ON OutputThe battery on (BATT ON) output indicates the status of the internal battery switchover comparator, which con-trols the internal V CC and BATT switches. For V CC greater than V BATT (ignoring the small hysteresis effect), BATT ON typically sinks 3.2mA at 0.4V. In bat-tery-backup mode, this output sources approximately 5mA. Use BATT ON to indicate battery switchover sta-tus, or to supply gate or base drive for an external pass transistor for higher current applications (see Typical Operating Circuit ).MAX807L/M/NFull-Featured µP Supervisory Circuit with±1.5% Reset Accuracy______________________________________________________________________________________13Figure 12. V CC and BATT-to-OUT SwitchTable 1. Input and Output Status in Battery-Backup ModeM A X 807L /M /NBATT OK OutputThe BATT OK comparator monitors the backup battery voltage, comparing it with a 2.265V reference (V CC ≥4V). BATT OK remains high as long as the backup bat-tery voltage remains above 2.265V, signaling that the backup battery has sufficient voltage to maintain the memory of static RAM. When the battery voltage drops below 2.265V, the BATT OK output drops low, signaling that the backup battery needs to be changed.__________Applications InformationThe MAX807 is not short-circuit protected. Shorting OUT to ground, other than power-up transients such as charging a decoupling capacitor, may destroy the device. If long leads connect to the IC’s inputs, ensure that these lines are free from ringing and other condi-tions that would forward bias the IC’s protection diodes.There are two distinct modes of operation:1)Normal Operating Mode, with all circuitry powered up. Typical supply current from V CC is 70µA, while only leakage currents flow from the battery.2)Battery-Backup Mode, where V CC is below V BATTand V RST . The supply current from the battery is typ-ically less than 1µA.Using SuperCaps™ orMaxCaps™ with the MAX807BATT has the same operating voltage range as V CC , and the battery-switchover threshold voltage is typically V BATT when V CC is decreasing or V BATT + 0.06V when V CC is increasing. This hysteresis allows use of aSuperCap (e.g., order of 0.47F) and a simple charging circuit as a backup source (Figure 13). Since V BATT can exceed V CC while V CC is above the reset threshold,there are no special precautions when using these µP supervisors with a SuperCap.Alternative Chip-Enable GatingUsing memory devices with CE and CE inputs allows the MAX807 CE loop to be bypassed. To do this, con-nect CE IN to ground, pull up CE OUT to OUT, and connect CE OUT to the CE input of each memory device (Figure 14). The CE input of each part then con-nects directly to the chip-select logic, which does not have to be gated by the MAX807.Adding Hysteresis to the Power-Fail ComparatorThe power-fail comparator has a typical input hystere-sis of 20mV. This is sufficient for most applications where a power-supply line is being monitored through an external voltage divider (Figure 10).Figure 15 shows how to add hysteresis to the power-fail comparator. Select the ratio of R1 and R2 such that PFI sees 2.265V when V IN falls to the desired trip point (V TRIP ). Resistor R3 adds hysteresis. It will typically be an order of magnitude greater than R1 or R2. The cur-rent through R1 and R2 should be at least 1µA to ensure that the 25nA (max) PFI input current does not shift the trip point. R3 should be larger than 10k Ωto prevent it from loading down the PFO pin. Capacitor C1adds additional noise rejection.Full-Featured µP Supervisory Circuit with ±1.5% Reset Accuracy 14______________________________________________________________________________________Figure 13. SuperCap or MaxCap on BATTFigure 14. Alternate CE GatingBackup-Battery ReplacementThe backup battery may be disconnected while V CC is above the reset threshold, provided BATT is bypassed with a 0.1µF capacitor to ground. No precautions are necessary to avoid spurious reset pulses.Negative-Going V CC TransientsWhile issuing resets to the µP during power-up, power-down, and brownout conditions, these supervisors are relatively immune to short-duration negative-going V CC transients (glitches). It is usually undesirable to reset the µP when V CC experiences only small glitches.The Typical Operating Characteristics show Maximum Transient Duration vs. Reset Comparator Overdrive, for which reset pulses are not generated. The graph was produced using negative-going V CC pulses, starting at 5V and ending below the reset threshold by the magni-tude indicated (reset comparator overdrive). The graph shows the maximum pulse width that a negative-going V CC transient may typically have without causing a reset pulse to be issued. As the amplitude of the tran-sient increases (i.e., goes farther below the reset threshold), the maximum allowable pulse width decreases.Typically, a V CC transient that goes 40mV below the reset threshold and lasts for 3µs or less will not cause a reset pulse to be issued.A 0.1µF bypass capacitor mounted close to the V CC pin provides additional transient immunity.Watchdog Software ConsiderationsTo help the watchdog timer keep a closer watch on soft-ware execution, you can use the method of setting and resetting the watchdog input at different points in the program, rather than “pulsing” the watchdog input high-low-high or low-high-low. This technique avoids a “stuck”loop where the watchdog timer continues to be reset within the loop, keeping the watchdog from timing out.Figure 16 shows an example flow diagram where the I/O driving the watchdog input is set high at the begin-ning of the program, set low at the beginning of every subroutine or loop, then set high again when the pro-gram returns to the beginning. If the program should “hang” in any subroutine, the I/O is continually set low and the watchdog timer is allowed to time out, causing a reset or interrupt to be issued.Maximum V CC Fall TimeThe V CC fall time is limited by the propagation delay of the battery switchover comparator and should not exceed 0.03V/µs. A standard rule for filter capacitance on most regulators is on the order of 100µF per amp of current. When the power supply is shut off or the main battery is disconnected, the associated initial V CC fall rate is just the inverse or 1A / 100µF = 0.01V/µs. The V CC fall rate decreases with time as V CC falls exponen-tially, which more than satisfies the maximum fall-time requirement.MAX807L/M/NFull-Featured µP Supervisory Circuit with±1.5% Reset Accuracy______________________________________________________________________________________15Figure 15. Adding Hysteresis to the Power-Fail ComparatorFigure 16. Watchdog Flow Diagram。

MAX706中文资料_数据手册_参数

__________Typical Operating Circuit
UNREGULATED DC
MAX667 +5V DC LINEAR
REGULATOR
PUSHBUTTON SWITCH
VCC
RESMR
MAX706 MAX813L
PFO
µP
VCC RESET I/O LINE NMI INTERRUPT
___________________________Features
o Available in Tiny µMAX Package
o Guaranteed RESET Valid at VCC = 1V o Precision Supply-Voltage Monitor
4.65V in MAX705/MAX707/MAX813L 4.40V in MAX706/MAX708
Output Current (all outputs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20mA Continuous Power Dissipation (TA = +70°C)
Plastic DIP (derate 9.09mW/°C above +70°C) . . . . . . . 727mW SO (derate 5.88mW/°C above +70°C) . . . . . . . . . . . . . . . 471mW µMAX (derate 4.10mW/°C above +70°C) . . . . . . . . . . . . 330mW
3) A 1.25V threshold detector for power-fail warning, low-battery detection, or for monitoring a power supply other than +5V.

MAX6627中文资料

General DescriptionThe MAX6627/MAX6628 precise digital temperature sensors report the temperature of a remote sensor. The remote sensor is a diode-connected transistor, typically a low-cost, easily mounted 2N3904 NPN type that replaces conventional thermistors or thermocouples.The MAX6627/MAX6628 can also measure the die tem-perature of other ICs, such as microprocessors (µPs) or microcontrollers (µCs) that contain an on-chip, diode-connected transistor.Remote accuracy is ±1°C when the temperature of the remote diode is between 0°C and +125°C and the tem-perature of the MAX6627/MAX6628 is +30°C. The tem-perature is converted to a 12-bit + sign word with 0.0625°C resolution. The architecture of the device is capable of interpreting data as high as +145°C from the remote sensor. The MAX6627/MAX6628 tempera-ture should never exceed +125°C.These sensors are 3-wire serial interface SPI™ compat-ible, allowing the MAX6627/MAX6628 to be readily con-nected to a variety of µCs. The MAX6627/MAX6628 are read-only devices, simplifying their use in systems where only temperature data is required.Two conversion rates are available, one that continu-ously converts data every 0.5s (MAX6627), and one that converts data every 8s (MAX6628). The slower ver-sion provides minimal power consumption under all operating conditions (30µA, typ). Either device can be read at any time and provide the data from the last con-version.Both devices operate with supply voltages between +3.0V and +5.5V, are specified between -55°C and +125°C, and come in the space-saving 8-pin SOT23package.ApplicationsHard Disk Drive Smart Battery Packs AutomotiveIndustrial Control Systems Notebooks, PCsFeatureso Accuracy±1°C (max) from 0°C ≤T RJ ≤+125°C, T A = +30°C ±2.4°C (max) from -55°C ≤T RJ ≤+100°C,0°C ≤T A ≤+70°C o 12-Bit + Sign, 0.0625°C Resolution o Low Power Consumption30µA (typ) (MAX6628)200µA (typ) (MAX6627)o Operating Temperature Range (-55°C to +125°C)o Measurement Temperature Range, Remote Junction (-55°C to +145°C)o 0.5s (MAX6627) or 8s (MAX6628) Conversion Rate o SPI-Compatible Interface o +3.0V to +5.5V Supply Range o 8-Pin SOT23 PackageMAX6627/MAX6628Remote ±1°C Accurate Digital Temperature Sensors with SPI-Compatible Serial Interface________________________________________________________________Maxim Integrated Products 119-2032; Rev 1; 7/01For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .Ordering InformationSPI is a trademark of Motorola, Inc.Pin Configuration appears at end of data sheet.M A X 6627/M A X 6628Remote ±1°C Accurate Digital Temperature Sensors with SPI-Compatible Serial InterfaceABSOLUTE MAXIMUM RATINGSStresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.All Voltages Referenced to GNDV CC ...........................................................................-0.3V to +6V SO, SCK, DXP, CS ........................................-0.3V to V CC + 0.3V DXN.......................................................................-0.3V to +0.8V SO Pin Current Range.........................................-1mA to +50mA Current Into All Other Pins..................................................10mA ESD Protection (Human Body Model).. (2000V)Continuous Power Dissipation (T A = +70°C)8-Pin SOT23 (derate 9.7mW/°C above +70°C)...........777mW Operating Temperature Range .........................-55°C to +125°C Junction Temperature......................................................+150°C Storage Temperature Range.............................-65°C to +150°C Lead Temperature (soldering, 10s)...................................Note 1ELECTRICAL CHARACTERISTICS(3.0V ≤V CC ≤5.5V, -55°C ≤T A ≤+125°C, unless otherwise noted. Typical values are at T A = +25°C, V CC = +3.3V, unless otherwise Note 1:This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the devicecan be exposed to during board-level solder attach and rework. This limit permits only the use of the solder profiles recommended in the industry-standard specification, JEDEC 020A, paragraph 7.6, Table 3 for I R/VPR and Convection Reflow. Preheating is required. Hand or wave soldering is not allowed.MAX6627/MAX6628Remote ±1°C Accurate Digital Temperature Sensors with SPI-Compatible Serial Interface_______________________________________________________________________________________3ELECTRICAL CHARACTERISTICS (continued)(3.0V ≤V= +25°C, V = +3.3V, unless otherwise Note 4:Serial timing characteristics guaranteed by design.M A X 6627/M A X 6628Remote ±1°C Accurate Digital Temperature Sensors with SPI-Compatible Serial Interface0501001502002503003.04.03.54.55.05.5AVERAGE OPERATING CURRENTvs. SUPPLY VOLTAGESUPPLY VOLTAGE (V)A V E R A G E O P E R A T I N G C U R R E N T (µA )-3-2-10123-55-5-3020457095120145TEMPERATURE ERROR vs. TEMPERATURETEMPERATURE (°C)T E M P E R A T U R E E R R O R(°C )0.61.00.81.41.21.81.62.02.42.22.6-55-52045-307095120145POWER-ON-RESET THRESHOLDvs. TEMPERATUREM A X 6627/8 t o c 03TEMPERATURE (°C)P O W E R -O N -R E S E T T H R E S H O L D (V )Typical Operating Characteristics(V CC = +3.3V, T A = +25°C, unless otherwise noted.)10100k10M 1k10010k1M100MTEMPERATURE ERROR vs.POWER-SUPPLY NOISE FREQUENCYFREQUENCY (Hz)T E M P E R A T U R E E R R O R (°C )0426810120255075100125-22468101214RESPONSE TO THERMAL SHOCKTIME (s)T E M P E R A T U R E (°C )13245M A X 6627/8 t o c 06CAPACITANCE (pF)T E M P E R A T U R E E R R O R (°C )10,000500015,00020,000TEMPERATURE ERROR vs. DXP/DXN CAPACITANCEMAX6627/MAX6628Remote ±1°C Accurate Digital Temperature Sensors with SPI-Compatible Serial InterfaceDetailed DescriptionThe MAX6627/MAX6628 remote digital thermometers report the temperature of a remote sensor. The remote sensor is a diode-connected transistor —typically, a low-cost, easily mounted 2N3904 NPN type —that replaces conventional thermistors or thermocouples.The MAX6627/MAX6628 can also measure the die tem-perature of other ICs, such as µPs or µCs, that contain an on-chip, diode-connected transistor.Remote accuracy is ±1°C when the temperature of the remote diode is between 0°C and +125°C and the tem-perature of the MAX6627/MAX6628 is +30°C. Data is available as a 12-bit + sign word with 0.0625°C resolu-tion. The operating range of the device extends from -55°C to +125°C, although the architecture of the device is capable of interpreting data up to +145°C.The device itself should never exceed +125°C.The MAX6627/MAX6628 are designed to work in con-junction with an external µC or other intelligent device serving as the master in thermostatic, process-control,or monitoring applications. The µC is typically a power management or keyboard controller, generating SPI serial commands by “bit-banging ” GPIO pins.Two conversion rates are available; the MAX6627 con-tinuously converts data every 0.5s, and the MAX6628continuously converts data every 8s. Either device can be read at any time and provide the data from the last conversion. The slower version provides minimal power consumption under all operating conditions. Or, by tak-ing CS low, any conversion in progress is stopped, and the rising edge of CS always starts a fresh conversion and resets the interface. This permits triggering a con-version at any time so that the power consumption of the MAX6627 can be overcome, if needed. Both devices operate with input voltages between +3.0V and +5.5V and are specified between -55°C and +125°C.The MAX6627 and MAX6628 come in space-saving 8-pin SOT23 packages.ADC Conversion SequenceThe device powers up as a free-running data converter (Figure 1). The CS pin can be used for conversion con-trol. The rising edge of CS resets the interface and starts a conversion. The falling edge of CS stops any conversion in progress, overriding the latency of the part. Temperature data from the previous completed conversion is available for read (Tables 1 and 2). I t is required to maintain CS high for a minimum of 320ms to complete a conversion.Idle ModePull CS low to enter idle mode. In idle mode, the ADC is not converting. The serial interface is still active and temperature data from the last completed conversion can still be read.Power-On ResetThe POR supply voltage of the MAX6627/MAX6628 is typically 1.6V. Below this supply voltage, the interface is inactive and the data register is set to the POR state,Figure 1. Free-Running Conversion Time and Rate RelationshipsTable 1. Data Output FormatM A X 6627/M A X 6628Remote ±1°C Accurate Digital Temperature Sensors with SPI-Compatible Serial Interface 6_______________________________________________________________________________________1.6V (typ), the device starts to convert, although tem-perature reading is not recommended at V CC levels below 3.0V.Serial InterfaceFigure 2 is the serial interface timing diagram. The data is latched into the shift register on the falling edge of the CS signal and then clocked out at the SO pin on the falling edge of SCK with the most-significant bit (MSB)first. There are 16 edges of data per frame. The last 2bits, D0 and D1, are always in high-Z mode. The falling edge of CS stops any conversion in progress, and the rising edge of CS always starts a new conversion and resets the interface. It is required to maintain a 320ms minimum pulse width of high CS signal before a con-version starts.Applications InformationRemote-Diode SelectionTemperature accuracy depends upon having a good-quality, diode-connected, small-signal transistor.Accuracy has been experimentally verified for all of the devices listed in Table 3. The MAX6627/MAX6628 can also directly measure the die temperature of CPUs and other ICs with on-board temperature-sensing diodes.The transistor must be a small-signal type with a rela-tively high forward voltage. This ensures that the input voltage is within the A/D input voltage range. The for-ward voltage must be greater than 0.25V at 10µA at the highest expected temperature. The forward voltage must be less than 0.95V at 100µA at the lowest expect-ed temperature. The base resistance has to be less than 100Ω. Tight specification of forward-current gain (+50 to +150, for example) indicates that the manufac-turer has good process control and that the devices have consistent characteristics.ADC Noise FilteringThe integrating ADC has inherently good noise rejec-tion, especially of low-frequency signals such as 60Hz/120Hz power-supply hum. Micropower operation places constraints on high-frequency noise y out the PC board carefully with proper external noise filtering for high-accuracy remote measurements in electrically noisy environments.Figure 2. SPI Timing DiagramTable 3. SOT23-Type Remote-Sensor the collector).Table 2. Temperature Data Format (Two ’s Complement)Filter high-frequency electromagnetic interference (EMI) at DXP and DXN with an external 2200pF capaci-tor connected between the two inputs. This capacitor can be increased to about 3300pF (max), including cable capacitance. A capacitance higher than 3300pF introduces errors due to the rise time of the switched-current source.PC Board Layout1)Place the MAX6627/MAX6628 as close as practicalto the remote diode. I n a noisy environment, such as a computer motherboard, this distance can be 4in to 8in, or more, as long as the worst noise sources (such as CRTs, clock generators, memory buses, and ISA/PCI buses) are avoided.2)Do not route the DXP/DXN lines next to the deflec-tion coils of a CRT. Also, do not route the traces across a fast memory bus, which can easily intro-duce +30°C error, even with good filtering.Otherwise, most noise sources are fairly benign.3)Route the DXP and DXN traces parallel and close toeach other, away from any high-voltage traces such as +12VDC. Avoid leakage currents from PC board contamination. A 20M Ωleakage path from DXP to ground causes approximately +1°C error.4)Connect guard traces to GND on either side of theDXP/DXN traces (Figure 3). With guard traces in place, routing near high-voltage traces is no longer an issue.5)Route as few vias and crossunders as possible tominimize copper/solder thermocouple effects. 6)When introducing a thermocouple, make sure thatboth the DXP and the DXN paths have matching thermocouples. In general, PC board-induced ther-mocouples are not a serious problem. A copper solder thermocouple exhibits 3µV/°C, and it takes approximately 200µV of voltage error at DXP/DXN to cause a +1°C measurement error, so most para-sitic thermocouple errors are swamped out.7)Use wide traces. Narrow traces are more inductiveand tend to pick up radiated noise. The 10mil widths and spacings recommended in Figure 3 are not absolutely necessary (as they offer only a minor improvement in leakage and noise), but use them where practical.8)Placing an electrically clean copper ground planebetween the DXP/DXN traces and traces carrying high-frequency noise signals helps reduce EMI.Twisted Pair and Shielded CablesFor remote-sensor distances longer than 8in, or in par-ticularly noisy environments, a twisted pair is recom-mended. I ts practical length is 6ft to 12ft (typ) before noise becomes a problem, as tested in a noisy elec-tronics laboratory. For longer distances, the best solu-tion is a shielded twisted pair like that used for audio microphones. For example, Belden #8451 works well for distances up to 100ft in a noisy environment.Connect the twisted pair to DXP and DXN and the shield to ground, and leave the shield ’s remote end unterminated. Excess capacitance at DXN or DXP limits practical remote-sensor distances (see Typical Operating Characteristics ).For very long cable runs, the cable ’s parasitic capaci-tance often provides noise filtering, so the recommend-ed 2200pF capacitor can often be removed or reduced in value. Cable resistance also affects remote-sensor accuracy. A 1Ωseries resistance introduces about +1/2°C error.MAX6627/MAX6628Remote ±1°C Accurate Digital Temperature Sensors with SPI-Compatible Serial Interface_______________________________________________________________________________________7Figure 3. Recommended DXP/DXN PC TracesM A X 6627/M A X 6628Chip InformationTRANSISTOR COUNT: 6241PROCESS: BiCMOSRemote ±1°C Accurate Digital Temperature Sensors with SPI-Compatible Serial Interface 8_______________________________________________________________________________________MAX6627/MAX6628Remote ±1°C Accurate Digital Temperature Sensors with SPI-Compatible Serial InterfaceMaxim cannot assume responsibility for use of any circuitry other than circuitry entirely embod ied in a Maxim prod uct. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________9©2001 Maxim Integrated ProductsPrinted USAis a registered trademark of Maxim Integrated Products.Package Information。

MAX479中文资料

元器件交易网
19-0127; Rev. 1; 11/98
17µA Max, Dual/Quad, Single-Supply, Precision Op Amps
_______________General Description
The MAX478 and MAX479 are dual and quad micropower, precision op amps available in 8-pin and 14-pin DIP and small-outline packages, respectively. Both devices feature an extremely low, 17µA max supply current per op amp, 70µV max offset voltage, 2.2µV/°C max offset voltage drift (0.5µV/°C typ), and 250pA max input offset current. The MAX478 and MAX479 operate from a single supply. The input voltage range includes ground, and the output swings to within a few millivolts of ground, which eliminates pull-down resistors and saves power. Both devices are optimized for single 3V and 5V supply operation, with guaranteed specifications at each supply voltage. Specifications for ±15V operation are also provided.

MAX832CWE中文资料

STEP-DOWN CONVER________________________________________________________________ Maxim Integrated Products
1
Call toll free 1-800-998-8800 for free samples or literature.
元器件交易网
5V/3.3V/3V/Adjustable-Output, 1A, Step-Down, PWM, Switch-Mode DC-DC Regulators MAX830–MAX833
ABSOLUTE MAXIMUM RATINGS
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V Switch Voltage with Respect to Input Voltage. . . . . . . . . . . . . . . . 50V Switch Voltage with Respect to GND (VSW negative) (Note 1). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V FB/SENSE Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V, +10V SHUT Voltage (not to exceed VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30V Note 1: Do not exceed switch-to-input voltage limitation.

MAX870中文资料

____________________________Features
o 5-Pin SOT23-5 Package o 99% Voltage Conversion Efficiency o Invert Input Supply Voltage o 0.7mA Quiescent Current (MAX870) o +1.4V to +5.5V Input Voltage Range o Require Only Two Capacitors o 25mA Output Current o Shutdown Control
* Dice are tested at TA = +25°C.
__________Typical Operating Circuit
__________________Pin Configuration
5
C1+
IN
2பைடு நூலகம்
INPUT SUPPLY VOLTAGE
TOP VIEW
MAX870 MAX871
元器件交易网
Switched-Capacitor Voltage Inverters
__________________________________________Typical Operating Characteristics
ABSOLUTE MAXIMUM RATINGS
IN to GND ..............................................................+6.0V to -0.3V OUT to GND ..........................................................-6.0V to +0.3V C1+ ..............................................................(VIN + 0.3V) to -0.3V C1-............................................................(VOUT - 0.3V) to +0.3V OUT Output Current ...........................................................50mA OUT Short Circuit to GND .............................................Indefinite Continuous Power Dissipation (TA = +70°C) SOT23-5 (derate 7.1mW/°C above +70°C)...................571mW Operating Temperature Range MAX870EUK/MAX871EUK ...............................-40°C to +85°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10sec) .............................+300°C

MAX713中文资料

BATTERY MANAGEMENT Jul 09, 1998 Switch-Mode Battery Charger Delivers 5AThe fast-charge controller IC3 (Figure 1) normally directs current to the battery via an external pnp transistor. In this circuit, the transistor is replaced with a 5A switching regulator (IC1) that delivers equivalent power with higher efficiency.Figure 1. By controlling the PWM duty cycle of switching regulator IC1, the fast-charge controller (IC3) makes efficient delivery of the battery's charging current.IC1 is a 5A buck switching regulator whose output is configured as a current source. Its internal power switch (an npn transistor) is relatively efficient because V CE(SAT) is small in comparison with the 15V-to-40V inputs. (For applications that require 2A or less, the low-saturation, non-Darlington power switch of a MAX726 offers better efficiency.)R6 senses the battery-charging current and enables IC3 to generate an analog drive signal at DRV. The signal is first attenuated by the op amp to assure stability by reducing gain in the control loop. It then drives IC1's compensation pin (VC), which gives direct access to the internal PWM comparator. IC3 thus controls the charging current via the PWM duty cycle of IC1. The Q1 buffer provides current to the DRV input.Loop stability is also determined by the feedback loop's dominant pole, set by C4 at the CC terminal of IC3. If you increase the value of the battery filter capacitor (C5), you should make a proportional increase in the value of C4. Lower values, however, assure good transient response. If your application produces load transients during the fast-charge cycle, check the worst-case response to a load step. To assure proper termination of the charge, battery voltage should settle within 2msec to 5mV times N (where N is the number of battery cells). More InformationMAX713:QuickView-- Full (PDF) Data Sheet-- Free Samples。

MAX1978中文数据手册

用于Peltier模块的集成温度控制器概论MAX1978 / MAX1979是用于Peltier热电冷却器（TEC）模块的最小, 最安全, 最精确完整的单芯片温度控制器。

片上功率FET和热控制环路电路可最大限度地减少外部元件, 同时保持高效率。

可选择的500kHz / 1MHz开关频率和独特的纹波消除方案可优化元件尺寸和效率, 同时降低噪声。

内部MOSFET的开关速度经过优化, 可降低噪声和EMI。

超低漂移斩波放大器可保持±0.001°C的温度稳定性。

直接控制输出电流而不是电压, 以消除电流浪涌。

独立的加热和冷却电流和电压限制提供最高水平的TEC保护。

MAX1978采用单电源供电, 通过在两个同步降压调节器的输出之间偏置TEC, 提供双极性±3A输出。

真正的双极性操作控制温度, 在低负载电流下没有“死区”或其他非线性。

当设定点非常接近自然操作点时, 控制系统不会捕获, 其中仅需要少量的加热或冷却。

模拟控制信号精确设置TEC 电流。

MAX1979提供高达6A的单极性输出。

提供斩波稳定的仪表放大器和高精度积分放大器, 以创建比例积分（PI）或比例积分微分（PID）控制器。

仪表放大器可以连接外部NTC或PTC热敏电阻, 热电偶或半导体温度传感器。

提供模拟输出以监控TEC温度和电流。

此外, 单独的过热和欠温输出表明当TEC温度超出范围时。

片上电压基准为热敏电阻桥提供偏置。

MAX1978 / MAX1979采用薄型48引脚薄型QFN-EP 封装, 工作在-40°C至+ 85°C温度范围。

采用外露金属焊盘的耐热增强型QFN-EP封装可最大限度地降低工作结温。

评估套件可用于加速设计。

应用光纤激光模块典型工作电路出现在数据手册的最后。

WDM, DWDM激光二极管温度控制光纤网络设备EDFA光放大器电信光纤接口ATE特征♦尺寸最小, 最安全, 最精确完整的单芯片控制器♦片上功率MOSFET-无外部FET♦电路占用面积<0.93in2♦回路高度<3mm♦温度稳定性为0.001°C♦集成精密积分器和斩波稳定运算放大器♦精确, 独立的加热和冷却电流限制♦通过直接控制TEC电流消除浪涌♦可调节差分TEC电压限制♦低纹波和低噪声设计♦TEC电流监视器♦温度监控器♦过温和欠温警报♦双极性±3A输出电流（MAX1978）♦单极性+ 6A输出电流（MAX1979）订购信息* EP =裸焊盘。

MAX247中文资料

General DescriptionThe MAX220–MAX249 family of line drivers/receivers is intended for all EIA/TIA-232E and V.28/V.24 communica-tions interfaces, particularly applications where ±12V is not available.These parts are especially useful in battery-powered sys-tems, since their low-power shutdown mode reduces power dissipation to less than 5µW. The MAX225,MAX233, MAX235, and MAX245/MAX246/MAX247 use no external components and are recommended for appli-cations where printed circuit board space is critical.________________________ApplicationsPortable Computers Low-Power Modems Interface TranslationBattery-Powered RS-232 Systems Multidrop RS-232 Networks____________________________Features Superior to Bipolaro Operate from Single +5V Power Supply (+5V and +12V—MAX231/MAX239)o Low-Power Receive Mode in Shutdown (MAX223/MAX242)o Meet All EIA/TIA-232E and V.28 Specifications o Multiple Drivers and Receiverso 3-State Driver and Receiver Outputs o Open-Line Detection (MAX243)Ordering InformationOrdering Information continued at end of data sheet.*Contact factory for dice specifications.MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers________________________________________________________________Maxim Integrated Products 1Selection Table19-4323; Rev 9; 4/00Power No. of NominalSHDN RxPart Supply RS-232No. of Cap. Value & Three-Active in Data Rate Number (V)Drivers/Rx Ext. Caps (µF)State SHDN (kbps)FeaturesMAX220+52/24 4.7/10No —120Ultra-low-power, industry-standard pinout MAX222+52/2 4 0.1Yes —200Low-power shutdownMAX223 (MAX213)+54/54 1.0 (0.1)Yes ✔120MAX241 and receivers active in shutdown MAX225+55/50—Yes ✔120Available in SOMAX230 (MAX200)+55/04 1.0 (0.1)Yes —120 5 drivers with shutdownMAX231 (MAX201)+5 and2/2 2 1.0 (0.1)No —120Standard +5/+12V or battery supplies; +7.5 to +13.2same functions as MAX232MAX232 (MAX202)+52/24 1.0 (0.1)No —120 (64)Industry standardMAX232A+52/240.1No —200Higher slew rate, small caps MAX233 (MAX203)+52/20— No —120No external capsMAX233A+52/20—No —200No external caps, high slew rate MAX234 (MAX204)+54/04 1.0 (0.1)No —120Replaces 1488MAX235 (MAX205)+55/50—Yes —120No external capsMAX236 (MAX206)+54/34 1.0 (0.1)Yes —120Shutdown, three stateMAX237 (MAX207)+55/34 1.0 (0.1)No —120Complements IBM PC serial port MAX238 (MAX208)+54/44 1.0 (0.1)No —120Replaces 1488 and 1489MAX239 (MAX209)+5 and3/52 1.0 (0.1)No —120Standard +5/+12V or battery supplies;+7.5 to +13.2single-package solution for IBM PC serial port MAX240+55/54 1.0Yes —120DIP or flatpack package MAX241 (MAX211)+54/54 1.0 (0.1)Yes —120Complete IBM PC serial port MAX242+52/240.1Yes ✔200Separate shutdown and enableMAX243+52/240.1No —200Open-line detection simplifies cabling MAX244+58/104 1.0No —120High slew rateMAX245+58/100—Yes ✔120High slew rate, int. caps, two shutdown modes MAX246+58/100—Yes ✔120High slew rate, int. caps, three shutdown modes MAX247+58/90—Yes ✔120High slew rate, int. caps, nine operating modes MAX248+58/84 1.0Yes ✔120High slew rate, selective half-chip enables MAX249+56/1041.0Yes✔120Available in quad flatpack packageFor free samples & the latest literature: , or phone 1-800-998-8800.For small orders, phone 1-800-835-8769.M A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/ReceiversABSOLUTE MAXIMUM RATINGS—MAX220/222/232A/233A/242/243ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243(V CC = +5V ±10%, C1–C4 = 0.1µF‚ MAX220, C1 = 0.047µF, C2–C4 = 0.33µF, T A = T MIN to T MAX ‚ unless otherwise noted.)Note 1:Input voltage measured with T OUT in high-impedance state, SHDN or V CC = 0V.Note 2:For the MAX220, V+ and V- can have a maximum magnitude of 7V, but their absolute difference cannot exceed 13V.Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.Supply Voltage (V CC )...............................................-0.3V to +6V Input VoltagesT IN ..............................................................-0.3V to (V CC - 0.3V)R IN (Except MAX220)........................................................±30V R IN (MAX220).....................................................................±25V T OUT (Except MAX220) (Note 1).......................................±15V T OUT (MAX220)...............................................................±13.2V Output VoltagesT OUT ...................................................................................±15V R OUT .........................................................-0.3V to (V CC + 0.3V)Driver/Receiver Output Short Circuited to GND.........Continuous Continuous Power Dissipation (T A = +70°C)16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)....842mW 18-Pin Plastic DIP (derate 11.11mW/°C above +70°C)....889mW20-Pin Plastic DIP (derate 8.00mW/°C above +70°C)..440mW 16-Pin Narrow SO (derate 8.70mW/°C above +70°C)...696mW 16-Pin Wide SO (derate 9.52mW/°C above +70°C)......762mW 18-Pin Wide SO (derate 9.52mW/°C above +70°C)......762mW 20-Pin Wide SO (derate 10.00mW/°C above +70°C)....800mW 20-Pin SSOP (derate 8.00mW/°C above +70°C)..........640mW 16-Pin CERDIP (derate 10.00mW/°C above +70°C).....800mW 18-Pin CERDIP (derate 10.53mW/°C above +70°C).....842mW Operating Temperature RangesMAX2_ _AC_ _, MAX2_ _C_ _.............................0°C to +70°C MAX2_ _AE_ _, MAX2_ _E_ _..........................-40°C to +85°C MAX2_ _AM_ _, MAX2_ _M_ _.......................-55°C to +125°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering, 10sec).............................+300°CMAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________3Note 3:MAX243 R2OUT is guaranteed to be low when R2IN is ≥0V or is floating.ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243 (continued)(V= +5V ±10%, C1–C4 = 0.1µF‚ MAX220, C1 = 0.047µF, C2–C4 = 0.33µF, T = T to T ‚ unless otherwise noted.)M A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 4_________________________________________________________________________________________________________________________________Typical Operating CharacteristicsMAX220/MAX222/MAX232A/MAX233A/MAX242/MAX243108-1051525OUTPUT VOLTAGE vs. LOAD CURRENT-4-6-8-2642LOAD CURRENT (mA)O U T P U T V O L T A G E (V )1002011104104060AVAILABLE OUTPUT CURRENTvs. DATA RATE65798DATA RATE (kbits/sec)O U T P U T C U R R E N T (m A )203050+10V-10VMAX222/MAX242ON-TIME EXITING SHUTDOWN+5V +5V 0V0V 500µs/div V +, V - V O L T A G E (V )MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________5V CC ...........................................................................-0.3V to +6V V+................................................................(V CC - 0.3V) to +14V V-............................................................................+0.3V to -14V Input VoltagesT IN ............................................................-0.3V to (V CC + 0.3V)R IN ......................................................................................±30V Output VoltagesT OUT ...................................................(V+ + 0.3V) to (V- - 0.3V)R OUT .........................................................-0.3V to (V CC + 0.3V)Short-Circuit Duration, T OUT ......................................Continuous Continuous Power Dissipation (T A = +70°C)14-Pin Plastic DIP (derate 10.00mW/°C above +70°C)....800mW 16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)....842mW 20-Pin Plastic DIP (derate 11.11mW/°C above +70°C)....889mW 24-Pin Narrow Plastic DIP(derate 13.33mW/°C above +70°C)..........1.07W24-Pin Plastic DIP (derate 9.09mW/°C above +70°C)......500mW 16-Pin Wide SO (derate 9.52mW/°C above +70°C).........762mW20-Pin Wide SO (derate 10 00mW/°C above +70°C).......800mW 24-Pin Wide SO (derate 11.76mW/°C above +70°C).......941mW 28-Pin Wide SO (derate 12.50mW/°C above +70°C) .............1W 44-Pin Plastic FP (derate 11.11mW/°C above +70°C).....889mW 14-Pin CERDIP (derate 9.09mW/°C above +70°C)..........727mW 16-Pin CERDIP (derate 10.00mW/°C above +70°C)........800mW 20-Pin CERDIP (derate 11.11mW/°C above +70°C)........889mW 24-Pin Narrow CERDIP(derate 12.50mW/°C above +70°C)..............1W24-Pin Sidebraze (derate 20.0mW/°C above +70°C)..........1.6W 28-Pin SSOP (derate 9.52mW/°C above +70°C).............762mW Operating Temperature RangesMAX2 _ _ C _ _......................................................0°C to +70°C MAX2 _ _ E _ _...................................................-40°C to +85°C MAX2 _ _ M _ _ ...............................................-55°C to +125°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering, 10sec).............................+300°CABSOLUTE MAXIMUM RATINGS—MAX223/MAX230–MAX241ELECTRICAL CHARACTERISTICS—MAX223/MAX230–MAX241(MAX223/230/232/234/236/237/238/240/241, V CC = +5V ±10; MAX233/MAX235, V CC = 5V ±5%‚ C1–C4 = 1.0µF; MAX231/MAX239,V CC = 5V ±10%; V+ = 7.5V to 13.2V; T A = T MIN to T MAX ; unless otherwise noted.)Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.M A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 6_______________________________________________________________________________________ELECTRICAL CHARACTERISTICS—MAX223/MAX230–MAX241 (continued)(MAX223/230/232/234/236/237/238/240/241, V CC = +5V ±10; MAX233/MAX235, V CC = 5V ±5%‚ C1–C4 = 1.0µF; MAX231/MAX239,V CC = 5V ±10%; V+ = 7.5V to 13.2V; T A = T MIN to T MAX ; unless otherwise noted.)MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________78.56.54.55.5TRANSMITTER OUTPUT VOLTAGE (V OH ) vs. V CC7.08.0V CC (V)V O H (V )5.07.57.46.02500TRANSMITTER OUTPUT VOLTAGE (V OH )vs. LOAD CAPACITANCE AT DIFFERENT DATA RATES6.46.27.27.0LOAD CAPACITANCE (pF)V O H (V )1500100050020006.86.612.04.02500TRANSMITTER SLEW RATE vs. LOAD CAPACITANCE6.05.011.09.010.0LOAD CAPACITANCE (pF)S L E W R A T E (V /µs )1500100050020008.07.0-6.0-9.04.55.5TRANSMITTER OUTPUT VOLTAGE (V OL ) vs. V CC-8.0-8.5-6.5-7.0V CC (V)V O L (V )5.0-7.5-6.0-7.62500TRANSMITTER OUTPUT VOLTAGE (V OL )vs. LOAD CAPACITANCE AT DIFFERENT DATA RATES-7.0-7.2-7.4-6.2-6.4LOAD CAPACITANCE (pF)V O L (V )150010005002000-6.6-6.810-105101520253035404550TRANSMITTER OUTPUT VOLTAGE (V+, V-)vs. LOAD CURRENT-2-6-4-886CURRENT (mA)V +, V - (V )420__________________________________________Typical Operating CharacteristicsMAX223/MAX230–MAX241*SHUTDOWN POLARITY IS REVERSED FOR NON MAX241 PARTSV+, V- WHEN EXITING SHUTDOWN(1µF CAPACITORS)MAX220-13SHDN*V-O V+500ms/divM A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 8_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGS—MAX225/MAX244–MAX249ELECTRICAL CHARACTERISTICS—MAX225/MAX244–MAX249(MAX225, V CC = 5.0V ±5%; MAX244–MAX249, V CC = +5.0V ±10%, external capacitors C1–C4 = 1µF; T A = T MIN to T MAX ; unless oth-erwise noted.)Note 4:Input voltage measured with transmitter output in a high-impedance state, shutdown, or V CC = 0V.Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.Supply Voltage (V CC )...............................................-0.3V to +6V Input VoltagesT IN ‚ ENA , ENB , ENR , ENT , ENRA ,ENRB , ENTA , ENTB ..................................-0.3V to (V CC + 0.3V)R IN .....................................................................................±25V T OUT (Note 3).....................................................................±15V R OUT ........................................................-0.3V to (V CC + 0.3V)Short Circuit (one output at a time)T OUT to GND............................................................Continuous R OUT to GND............................................................ContinuousContinuous Power Dissipation (T A = +70°C)28-Pin Wide SO (derate 12.50mW/°C above +70°C).............1W 40-Pin Plastic DIP (derate 11.11mW/°C above +70°C)...611mW 44-Pin PLCC (derate 13.33mW/°C above +70°C)...........1.07W Operating Temperature RangesMAX225C_ _, MAX24_C_ _ ..................................0°C to +70°C MAX225E_ _, MAX24_E_ _ ...............................-40°C to +85°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering,10sec)..............................+300°CMAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________9Note 5:The 300Ωminimum specification complies with EIA/TIA-232E, but the actual resistance when in shutdown mode or V CC =0V is 10M Ωas is implied by the leakage specification.ELECTRICAL CHARACTERISTICS—MAX225/MAX244–MAX249 (continued)(MAX225, V CC = 5.0V ±5%; MAX244–MAX249, V CC = +5.0V ±10%, external capacitors C1–C4 = 1µF; T A = T MIN to T MAX ; unless oth-erwise noted.)M A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 10________________________________________________________________________________________________________________________________Typical Operating CharacteristicsMAX225/MAX244–MAX24918212345TRANSMITTER SLEW RATE vs. LOAD CAPACITANCE86416LOAD CAPACITANCE (nF)T R A N S M I T T E R S L E W R A T E (V /µs )14121010-105101520253035OUTPUT VOLTAGEvs. LOAD CURRENT FOR V+ AND V--2-4-6-88LOAD CURRENT (mA)O U T P U T V O L T A G E (V )64209.05.012345TRANSMITTER OUTPUT VOLTAGE (V+, V-)vs. LOAD CAPACITANCE AT DIFFERENT DATA RATES6.05.58.5LOAD CAPACITANCE (nF)V +, V (V )8.07.57.06.5MAX220–MAX249Drivers/Receivers______________________________________________________________________________________11Figure 1. Transmitter Propagation-Delay Timing Figure 2. Receiver Propagation-Delay TimingFigure 3. Receiver-Output Enable and Disable Timing Figure 4. Transmitter-Output Disable TimingM A X 220–M A X 249Drivers/Receivers 12______________________________________________________________________________________ENT ENR OPERATION STATUS TRANSMITTERSRECEIVERS00Normal Operation All Active All Active 01Normal Operation All Active All 3-State10Shutdown All 3-State All Low-Power Receive Mode 11ShutdownAll 3-StateAll 3-StateTable 1a. MAX245 Control Pin ConfigurationsENT ENR OPERATION STATUS TRANSMITTERS RECEIVERSTA1–TA4TB1–TB4RA1–RA5RB1–RB500Normal Operation All Active All Active All Active All Active 01Normal Operation All Active All Active RA1–RA4 3-State,RA5 Active RB1–RB4 3-State,RB5 Active 1ShutdownAll 3-StateAll 3-StateAll Low-Power Receive Mode All Low-Power Receive Mode 11Shutdown All 3-State All 3-StateRA1–RA4 3-State,RA5 Low-Power Receive ModeRB1–RB4 3-State,RB5 Low-Power Receive ModeTable 1b. MAX245 Control Pin ConfigurationsTable 1c. MAX246 Control Pin ConfigurationsENA ENB OPERATION STATUS TRANSMITTERS RECEIVERSTA1–TA4TB1–TB4RA1–RA5RB1–RB500Normal Operation All Active All Active All Active All Active 01Normal Operation All Active All 3-State All Active RB1–RB4 3-State,RB5 Active 1ShutdownAll 3-StateAll ActiveRA1–RA4 3-State,RA5 Active All Active 11Shutdown All 3-State All 3-StateRA1–RA4 3-State,RA5 Low-Power Receive ModeRB1–RB4 3-State,RA5 Low-Power Receive ModeMAX220–MAX249Drivers/Receivers______________________________________________________________________________________13Table 1d. MAX247/MAX248/MAX249 Control Pin ConfigurationsM A X 220–M A X 249_______________Detailed DescriptionThe MAX220–MAX249 contain four sections: dual charge-pump DC-DC voltage converters, RS-232 dri-vers, RS-232 receivers, and receiver and transmitter enable control inputs.Dual Charge-Pump Voltage ConverterThe MAX220–MAX249 have two internal charge-pumps that convert +5V to ±10V (unloaded) for RS-232 driver operation. The first converter uses capacitor C1 to dou-ble the +5V input to +10V on C3 at the V+ output. The second converter uses capacitor C2 to invert +10V to -10V on C4 at the V- output.A small amount of power may be drawn from the +10V (V+) and -10V (V-) outputs to power external circuitry (see the Typical Operating Characteristics section),except on the MAX225 and MAX245–MAX247, where these pins are not available. V+ and V- are not regulated,so the output voltage drops with increasing load current.Do not load V+ and V- to a point that violates the mini-mum ±5V EIA/TIA-232E driver output voltage when sourcing current from V+ and V- to external circuitry. When using the shutdown feature in the MAX222,MAX225, MAX230, MAX235, MAX236, MAX240,MAX241, and MAX245–MAX249, avoid using V+ and V-to power external circuitry. When these parts are shut down, V- falls to 0V, and V+ falls to +5V. For applica-tions where a +10V external supply is applied to the V+pin (instead of using the internal charge pump to gen-erate +10V), the C1 capacitor must not be installed and the SHDN pin must be tied to V CC . This is because V+is internally connected to V CC in shutdown mode.RS-232 DriversThe typical driver output voltage swing is ±8V when loaded with a nominal 5k ΩRS-232 receiver and V CC =+5V. Output swing is guaranteed to meet the EIA/TIA-232E and V.28 specification, which calls for ±5V mini-mum driver output levels under worst-case conditions.These include a minimum 3k Ωload, V CC = +4.5V, and maximum operating temperature. Unloaded driver out-put voltage ranges from (V+ -1.3V) to (V- +0.5V). Input thresholds are both TTL and CMOS compatible.The inputs of unused drivers can be left unconnected since 400k Ωinput pull-up resistors to V CC are built in (except for the MAX220). The pull-up resistors force the outputs of unused drivers low because all drivers invert.The internal input pull-up resistors typically source 12µA,except in shutdown mode where the pull-ups are dis-abled. Driver outputs turn off and enter a high-imped-ance state—where leakage current is typically microamperes (maximum 25µA)—when in shutdownmode, in three-state mode, or when device power is removed. Outputs can be driven to ±15V. The power-supply current typically drops to 8µA in shutdown mode.The MAX220 does not have pull-up resistors to force the ouputs of the unused drivers low. Connect unused inputs to GND or V CC .The MAX239 has a receiver three-state control line, and the MAX223, MAX225, MAX235, MAX236, MAX240,and MAX241 have both a receiver three-state control line and a low-power shutdown control. Table 2 shows the effects of the shutdown control and receiver three-state control on the receiver outputs.The receiver TTL/CMOS outputs are in a high-imped-ance, three-state mode whenever the three-state enable line is high (for the MAX225/MAX235/MAX236/MAX239–MAX241), and are also high-impedance whenever the shutdown control line is high.When in low-power shutdown mode, the driver outputs are turned off and their leakage current is less than 1µA with the driver output pulled to ground. The driver output leakage remains less than 1µA, even if the transmitter output is backdriven between 0V and (V CC + 6V). Below -0.5V, the transmitter is diode clamped to ground with 1k Ωseries impedance. The transmitter is also zener clamped to approximately V CC + 6V, with a series impedance of 1k Ω.The driver output slew rate is limited to less than 30V/µs as required by the EIA/TIA-232E and V.28 specifica-tions. Typical slew rates are 24V/µs unloaded and 10V/µs loaded with 3Ωand 2500pF.RS-232 ReceiversEIA/TIA-232E and V.28 specifications define a voltage level greater than 3V as a logic 0, so all receivers invert.Input thresholds are set at 0.8V and 2.4V, so receivers respond to TTL level inputs as well as EIA/TIA-232E and V.28 levels.The receiver inputs withstand an input overvoltage up to ±25V and provide input terminating resistors withDrivers/Receivers 14Table 2. Three-State Control of ReceiversMAX220–MAX249Drivers/Receivers______________________________________________________________________________________15nominal 5k Ωvalues. The receivers implement Type 1interpretation of the fault conditions of V.28 and EIA/TIA-232E.The receiver input hysteresis is typically 0.5V with a guaranteed minimum of 0.2V. This produces clear out-put transitions with slow-moving input signals, even with moderate amounts of noise and ringing. The receiver propagation delay is typically 600ns and is independent of input swing direction.Low-Power Receive ModeThe low-power receive-mode feature of the MAX223,MAX242, and MAX245–MAX249 puts the IC into shut-down mode but still allows it to receive information. This is important for applications where systems are periodi-cally awakened to look for activity. Using low-power receive mode, the system can still receive a signal that will activate it on command and prepare it for communi-cation at faster data rates. This operation conserves system power.Negative Threshold—MAX243The MAX243 is pin compatible with the MAX232A, differ-ing only in that RS-232 cable fault protection is removed on one of the two receiver inputs. This means that control lines such as CTS and RTS can either be driven or left floating without interrupting communication. Different cables are not needed to interface with different pieces of equipment.The input threshold of the receiver without cable fault protection is -0.8V rather than +1.4V. Its output goes positive only if the input is connected to a control line that is actively driven negative. If not driven, it defaults to the 0 or “OK to send” state. Normally‚ the MAX243’s other receiver (+1.4V threshold) is used for the data line (TD or RD)‚ while the negative threshold receiver is con-nected to the control line (DTR‚ DTS‚ CTS‚ RTS, etc.). Other members of the RS-232 family implement the optional cable fault protection as specified by EIA/TIA-232E specifications. This means a receiver output goes high whenever its input is driven negative‚ left floating‚or shorted to ground. The high output tells the serial communications IC to stop sending data. To avoid this‚the control lines must either be driven or connected with jumpers to an appropriate positive voltage level.Shutdown—MAX222–MAX242On the MAX222‚ MAX235‚ MAX236‚ MAX240‚ and MAX241‚ all receivers are disabled during shutdown.On the MAX223 and MAX242‚ two receivers continue to operate in a reduced power mode when the chip is in shutdown. Under these conditions‚ the propagation delay increases to about 2.5µs for a high-to-low input transition. When in shutdown, the receiver acts as a CMOS inverter with no hysteresis. The MAX223 and MAX242 also have a receiver output enable input (EN for the MAX242 and EN for the MAX223) that allows receiver output control independent of SHDN (SHDN for MAX241). With all other devices‚ SHDN (SH DN for MAX241) also disables the receiver outputs.The MAX225 provides five transmitters and five receivers‚ while the MAX245 provides ten receivers and eight transmitters. Both devices have separate receiver and transmitter-enable controls. The charge pumps turn off and the devices shut down when a logic high is applied to the ENT input. In this state, the supply cur-rent drops to less than 25µA and the receivers continue to operate in a low-power receive mode. Driver outputs enter a high-impedance state (three-state mode). On the MAX225‚ all five receivers are controlled by the ENR input. On the MAX245‚ eight of the receiver out-puts are controlled by the ENR input‚ while the remain-ing two receivers (RA5 and RB5) are always active.RA1–RA4 and RB1–RB4 are put in a three-state mode when ENR is a logic high.Receiver and Transmitter EnableControl InputsThe MAX225 and MAX245–MAX249 feature transmitter and receiver enable controls.The receivers have three modes of operation: full-speed receive (normal active)‚ three-state (disabled)‚ and low-power receive (enabled receivers continue to function at lower data rates). The receiver enable inputs control the full-speed receive and three-state modes. The transmitters have two modes of operation: full-speed transmit (normal active) and three-state (disabled). The transmitter enable inputs also control the shutdown mode. The device enters shutdown mode when all transmitters are disabled. Enabled receivers function in the low-power receive mode when in shutdown.M A X 220–M A X 249Tables 1a–1d define the control states. The MAX244has no control pins and is not included in these tables. The MAX246 has ten receivers and eight drivers with two control pins, each controlling one side of the device. A logic high at the A-side control input (ENA )causes the four A-side receivers and drivers to go into a three-state mode. Similarly, the B-side control input (ENB ) causes the four B-side drivers and receivers to go into a three-state mode. As in the MAX245, one A-side and one B-side receiver (RA5 and RB5) remain active at all times. The entire device is put into shut-down mode when both the A and B sides are disabled (ENA = ENB = +5V).The MAX247 provides nine receivers and eight drivers with four control pins. The ENRA and ENRB receiver enable inputs each control four receiver outputs. The ENTA and ENTB transmitter enable inputs each control four drivers. The ninth receiver (RB5) is always active.The device enters shutdown mode with a logic high on both ENTA and ENTB .The MAX248 provides eight receivers and eight drivers with four control pins. The ENRA and ENRB receiver enable inputs each control four receiver outputs. The ENTA and ENTB transmitter enable inputs control four drivers each. This part does not have an always-active receiver. The device enters shutdown mode and trans-mitters go into a three-state mode with a logic high on both ENTA and ENTB .The MAX249 provides ten receivers and six drivers with four control pins. The ENRA and ENRB receiver enable inputs each control five receiver outputs. The ENTA and ENTB transmitter enable inputs control three dri-vers each. There is no always-active receiver. The device enters shutdown mode and transmitters go into a three-state mode with a logic high on both ENTA and ENTB . In shutdown mode, active receivers operate in a low-power receive mode at data rates up to 20kbits/sec.__________Applications InformationFigures 5 through 25 show pin configurations and typi-cal operating circuits. In applications that are sensitive to power-supply noise, V CC should be decoupled to ground with a capacitor of the same value as C1 and C2 connected as close as possible to the device.Drivers/Receivers16______________________________________________________________________________________。

宏测MTS7000测试系统硬件手册 V2.4

MS7000测试系统硬件手册Version2.4All Rights Reserved上海宏测半导体科技有限公司MacroTest Semiconductor,Inc.目录引言 (4)第1章系统概述 (5)1.1系统结构 (5)1.2系统配置 (5)1.3系统通讯接口 (6)1.4系统软件环境 (6)1.5系统电源 (6)1.6系统重量尺寸 (6)1.7系统使用环境 (6)第2章系统原理结构及指标 (7)2.1系统组成 (7)2.2电源模块 (8)2.3数据控制模块 (8)2.3.1数据控制模块原理框图 (8)2.3.2数据控制模块TTL接口信号定义 (9)2.4DVI Option (9)2.4.1DVI Option原理框图 (9)2.4.2DVI Option配置说明 (10)2.4.3DVI Option参数指标 (11)2.5DVI10Option (12)2.5.1DVI10Option原理框图 (12)2.5.2DVI10Option配置说明 (13)2.5.3DVI10Option参数指标 (14)2.6OVI&OVIS Option (15)2.6.1OVI Option原理框图 (16)2.6.2OVI Option配置说明 (16)2.6.3OVI Option参数指标 (17)2.7QVI&QVIS Option (18)2.7.1QVI Option原理框图 (19)2.7.2QVI Option配置说明 (19)2.7.3QVI Option参数指标 (20)2.8ACS Option (21)2.8.1ACS Option原理框图 (22)2.8.2ACS Option配置说明及参数指标 (22)2.9TMU&TMUS Option (23)2.9.1TMU Option原理框图 (24)2.9.2TMU Option配置说明 (24)2.9.3TMU Option参数指标 (25)2.10DCBL Option (26)2.10.2DCBL Option配置说明及参数指标 (26)2.10.1DCBL Option原理框图 (27)2.11AWG Option (29)2.11.1AWG Option原理框图 (29)2.11.2AWG Option配置说明及参数指标 (29)2.12FHVI Option (30)2.12.1FHVI Option原理框图 (31)2.12.2FHVI Option配置说明及参数指标 (31)2.12.3FHVI出线接口定义 (32)2.12.4FHVI使用说明 (32)第3章系统资源及用户接口定义 (33)3.1用户电源 (33)3.2用户继电器驱动 (33)3.3用户扩展总线 (33)3.4TTL接口定义 (33)3.5IEEE488/GPIB接口信号定义 (35)第4章系统自检及校准 (36)4.1系统自检 (36)4.2系统校准 (36)第5章维护保养 (37)5.1维护指导 (37)5.1.1故障诊断 (37)5.1.2故障检修 (37)5.1.3维护咨询 (37)5.2保养程序 (37)5.2.1一级保养 (37)5.2.2二级保养 (37)5.2.3三级保养 (37)5.2.4维护保养记录存档 (37)第6章资源信号接口定义 (38)6.1J1接口定义 (38)6.2J2接口定义 (39)6.3J3接口定义 (40)6.4J4接口定义 (41)6.5J5接口定义 (42)6.6J6接口定义 (44)6.7J7接口定义 (46)6.8J8接口定义 (48)6.9J9接口定义 (50)6.10J10接口定义 (51)附件：参考资料 (52)引言欢迎使用MS7000测试系统，MS7000是MTS新一代的数模混合测试系统，MS7000采用全新的系统架构，拥有丰富的用户资源，是一款高效低成本的测试系统。

MAX3227中文资料

元器件交易网
19-1289; Rev 1; 3/98
1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus
________________General Description
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: , or phone 1-800-998-8800. For small orders, phone 408-737-7600 ext. 3468.
MAX3224 MAX3225 MAX3226 MAX3227 MAX3244 MAX3245
AutoShutdownPlus and MegaBaud are trademarks of Maxim Integrated Products.
†Covered by U.S. Patent numbers 4,636,930; 4,679,134; 4,777,577; 4,797,899; 4,809,152; 4,897,774; 4,999,761;5,649,210; and other patents pending.
元器件交易网
1µA Supply Current, 1Mbps, 3.0V to 5.5V, RS-232 Transceivers with AutoShutdown Plus MAX3224–MAX3227/MAX3244/MAX3245

XC61CN替换MAX6377和MAX6380及MAX6808

XC61CN替换MAX6377和MAX6380及MAX6808例：XC61CN 替换MAX6377XC61CN 替换MAX6380XC61CN 替换MAX6808系列名称：【XC61CN/XC61CC】特点：低功耗(0.8V)输入电压(V)：最小--0.8V；最大--6V输出电压(V)：最小--0.7V；最大--10V最大输出电流(mA)：400mA消耗电流(μA)：0.7A封装：SOT-23，SOT-89，SSOT-24，TO-92【TOREX-XC61CN系列】描述：1.XC61CN系列是一款高精度,低功耗的电压检测器芯片,并采用了CMOS生产工艺和激光微调技术。

2.XC61CN系列受温度漂移特性的影响很小,电压检测精度很高。

3.XC61CN系列有CMOS和N沟道开漏两种输出模式供选择。

【TOREX-XC61CN系列】特点：●高精度：±2%, ±1% (VDF=2.6V~5.1V)●低消耗电流：0.7μA(TYP.)[VIN=1.5V]●检测电压范围：能够在0.8V～6.0V范围内以0.1V间隔设定●工作电压范围：0.7V～6.0V(低检测电压0.8V～1.5V), 0.7V～10.0V(一般检测电压1.6V～6.0V)●检测电压温度特性：±100ppm/℃(TYP.)●輸出形式：N沟道开漏/CMOS輸出●封装：SSOT-24, SOT-23, SOT-89, TO-92TOREX日本IC均可完全替代下列型号:XC6221Bxx2MR 替代MIC5253 XC6115xxxxMR 替代LTC699CN8 XC6221BXX2MR 替代MIC5255-xxBM5 XC6116x0xxMR 替代LTC2915xxS8 XC6221BXX2MR 替代MIC5259 XC6121 替代MAX6320XC6204Bxx2DR 替代MIC5305-xxYML XC6122 替代MAX6320XC6419 替代MIC5371 XC6123 替代MAX6320XB1086 替代MIC39100-xxBS XC6124 替代MAX6320XC6205 替代MIC5203 XC6113 替代MAX823XC6411 替代MIC5371 XC6103 替代MAX823XC6412 替代MIC5371 XC6112 替代MAX823XC6415 替代MIC5371 XC6102 替代MAX823XCM406 替代MIC5264 XC6115 替代MAX824XC8101 替代MIC94060 XC6105 替代MAX824XC6601 替代MCP1727 XC6114xxxxMR 替代DS1819BRXC6213 替代TC1014-xxVCT713 XC6104xxxxMR 替代DS1819BRXC6212 替代TC1014-xxVCT713 XC61H 替代MAX809/803XC62KNxx02PR 替代TC59xx02EMBTR XC6101xxxxMR 替代DS1819ARXC62KNxx02MR 替代TC59xx02ECB XC6106xxxxER 替代MAX6335XC62EPxxxxMR 替代TC57xx02ECT XC6106xxxxER 替代MAX6402XC6206Pxx2TB替代TC55RPxx02EZB XC6107 替代MAX825XC6206Pxx2PR 替代TC55RPxx02EMB XC6116xxxxER 替代MAX6402XC6206Pxx2MR 替代TC55RPxx01ECB XC612 替代MAX6779XC6203Pxx2FR 替代TC1264-xxVDB XC61CNxx02NR 替代MAX6377XRxx XC6207 替代TC1014-xxVCT713 XC61CNxx02NR 替代MAX6380XRxx XC6217 替代TC1014-xxVCT XC61CNxx02MR 替代MAX6808URxx XC6206Pxx2PR 替代MCP1700T-xx02E/TT XC61FC 替代MAX809XC6209Bxx2MR 替代TC1014-xxVCT713 XC61FC2912MR 替代MAX809SEUR XC6209Bxx2MR 替代TC1015xxVCT XC61CCxx02NR 替代MAX6375XRxx XC6209Bxx2MR 替代TC1185xxVCT XC61CCxx02NR 替代MAX6378XRxx XC6203Pxx2FR 替代TC1262-xxVDB XC61CCxx02MR 替代MAX6806URxx XC6204Bxx2MR 替代LX8211-xxISE XC6111xxxxMR 替代DS1819ARXC6215Pxx2NR 替代MC78LC00 XC6101 替代MAX823XC6210Bxx2 替代MC78M00 XC6111 替代MAX823XC6401CHxxMR 替代LP3988IMX-xx XC6104 替代MAX824XC6403DHxxMR 替代LP3988IMF-xx XC6114 替代MAX824XC6210B122DR 替代LP3990TL-xx XC6106 替代MAX825XC6210B122DR 替代LP3990MF-xx XC6116 替代MAX825XC6221A182MR 替代LP3990MF-xx XC6107xxxxMR 替代MAX6337USxxD3 XC6202Pxx2TH 替代LM2931AZxx XC6117xxxxMR 替代MAX6337USxxD3 XC6214 替代LM1117MPX-xx XC6107xxxxMR 替代MAX6841/2XC6419 替代LP5996 XC6117xxxxMR 替代MAX6841/2XC6411 替代LP5996 XC61FNxxx2MR 替代MAX803XC6412 替代LP5996 XC61CNxx02MR 替代MAX6380URXC6415 替代LP5996 XC61CCxx02MR 替代MAX6375URXB1086Pxx1JR 替代LM1086CS XC6117 替代MAX825XB1117K12BFR 替代LM1117S XC6106 替代MIC2775XB1117PxxxFR 替代LM1117MPX-xx XC6116 替代MIC2775XC6203Pxx2FR 替代LM1117MPX-xx XC612 替代MIC2777XC6202Pxx2TH 替代LM2936Z-xx XCM410 替代MIC2774XB1117Pxx1FR 替代LM340S XC61CCxx02PR 替代TC54VCxx02EMB XC6202Pxx2TH 替代LM340LAZ-xx XC61CCxx02TB 替代TC54VCxx02EZB XC6202Pxx2MR 替代LM3480IM3-xx XC61H 替代TCM809XC6203P332FR 替代LM3940IMP-3.3 XCM410 替代TC52XC6202Pxx2TH 替代LM78LxxACZ XC6120 替代TC54XC6404DHxxMR 替代LMS5258MF-xx XC612 替代TC52XC6202Pxx2MR 替代LP2950 XC61CNxx02MR 替代TC53Nxx02ECTTR XC6204Bxx2MR 替代LP2978 XC61CNxx02NR 替代TC53Nxx02EVCTR XC6204Bxx2MR 替代LP2980AIM5-xx XC61CN 替代TC54VNXC6204Bxx2MR 替代LP2980IM5-xx XC6202Pxx2TH 替代L4931ABZxxXC6204Axx2MR 替代LP2980IM5X-xx XC6202Pxx2TH 替代L4931CZxxXC6204Bxx2MR 替代LP2981AIM5-xx XC6202Pxx2PR 替代L78LxxABUTRXC6204Bxx2MR 替代LP2981IM5-xx XC6202Pxx2TH 替代L78LxxABZXC6204Bxx2MR 替代LP2982AIM5-xx XC6202Pxx2PR 替代L78LxxACUXC6204Bxx2MR 替代LP2982IM5-xx XC6202Pxx2TH 替代L78LxxACZXC6204Bxx2MR 替代LP2985AIM5-xx XC6202Pxx2TH 替代L78LxxCZXC6204Bxx2MR 替代LP2985IM5-xx XC6203Pxx2FR 替代LD1117SXC6204Bxx2MR 替代LP3984IBP-xx XC6204Bxx2MR 替代LD2979MxxXC6403 替代LP3982 XC6202Pxx2TH 替代LD2979ZxxXC6204Bxx2DR 替代LP3985IBL-xx XC6204Bxx2MR 替代LD2980ABMxxXC6204Bxx2MR 替代LP3985IM5-x.x XC6201Pxx2PR 替代LD2980ABUxxTR XC62H 替代NCP584HSNxxT1G XC6204Bxx2MR 替代LD2980ACMxxXC62E 替代NCP584HSNxxT1G XC6201Pxx2PR 替代LD2980ACUxxXC6404 替代NCP400FCT2G XC6204Bxx2MR 替代LD2981ABMxxXB1086 替代LM317MBDTRK XC6201Pxx2PR 替代LD2981ABUxxXC6202 series 替代LM2931CD XC6204Bxx2MR 替代LD2981ACMxxXC6202Pxx2TH 替代LM2931Z-xx XC6201Pxx2PR 替代LD2981ACUxxXC6202Pxx2MR 替代LP2950 XC6202Pxx2TH 替代LExxABZ/CZXC6202Pxx2TH 替代LP2950CZ-xx XC6401 替代NCP583XVxxT2G XB1086 替代MC33269DTRK XC6214 替代MC78LCxxHT1XC6203Pxx2FR 替代MC33275ST-xxT3 XC6219 替代NCP584HSNxxT1G XC6204Bxx2MR 替代MC33761 XC6219Bxx2MR 替代BAxxxLBSGXC6206Pxx2PR 替代MC78FCxxHT1 XC6219 替代BA0xxLBSGXC6203xxx2PR 替代MC78LCxxHT1 XC6206Pxx2TB 替代RE5RExxACXC6202Pxx2TH 替代MC78LxxACP/BCP XC6206Pxx2PR 替代RH5RLxxAAXC6204Bxx2MR 替代MC78PCxxNTR XC6206Pxx2TH 替代RE5RLxxAAXC6206Pxx2PR 替代MC78RCxxHT1 XC6206Pxx2TB 替代RE5RLxxACXC6217Axx2MR 替代NCP584HSNxxT1G XC62EPxx02MR 替代RN5RGxxAATR XC6203Pxx2FR 替代SC5201-1GSTR3 XC62H 替代RN5RGxxAATR XC6402 替代NCP400FCT2G XC6419 替代R5325XC6403/04 替代NCP400FCT2G XB1086 替代RN5RGxxAATR XC6405 替代NCP400FCT2G XC6411 替代R5325XC6204Bxx2MR 替代R1111Nxx1A/B XC6412 替代R5325XC6204Bxx2MR 替代R1112Nxx1A/B XC6415 替代R5325XC6204Bxx2MR 替代R1112Nxx1B-TR XC8101 替代R5520HXC6206Pxx2PR 替代RH5RExxAA XC6204Bxx2MR 替代R1110Nxx1A/BXC6206Pxx2TH 替代RE5RExxAA。

MAX1978中文数据手册

用于Peltier模块的集成温度控制器概论MAX1978 / MAX1979是用于Peltier热电冷却器（TEC）模块的最小，最安全，最精确完整的单芯片温度控制器。

片上功率FET和热控制环路电路可最大限度地减少外部元件，同时保持高效率。

可选择的500kHz / 1MHz开关频率和独特的纹波消除方案可优化元件尺寸和效率，同时降低噪声。

内部MOSFET的开关速度经过优化，可降低噪声和EMI。

超低漂移斩波放大器可保持±0.001°C 的温度稳定性。

直接控制输出电流而不是电压，以消除电流浪涌。

独立的加热和冷却电流和电压限制提供最高水平的TEC保护。

MAX1978采用单电源供电，通过在两个同步降压调节器的输出之间偏置TEC，提供双极性±3A输出。

真正的双极性操作控制温度，在低负载电流下没有“死区”或其他非线性。

当设定点非常接近自然操作点时，控制系统不会捕获，其中仅需要少量的加热或冷却。

模拟控制信号精确设置TEC电流。

MAX1979提供高达6A的单极性输出。

提供斩波稳定的仪表放大器和高精度积分放大器，以创建比例积分（PI）或比例积分微分（PID）控制器。

仪表放大器可以连接外部NTC或PTC热敏电阻，热电偶或半导体温度传感器。

提供模拟输出以监控TEC 温度和电流。

此外，单独的过热和欠温输出表明当TEC温度超出范围时。

片上电压基准为热敏电阻桥提供偏置。

MAX1978 / MAX1979采用薄型48引脚薄型QFN-EP封装，工作在-40°C至+ 85°C温度范围。

采用外露金属焊盘的耐热增强型QFN-EP封装可最大限度地降低工作结温。

评估套件可用于加速设计。

应用光纤激光模块典型工作电路出现在数据手册的最后。

WDM，DWDM激光二极管温度控制光纤网络设备EDFA光放大器电信光纤接口ATE特征♦尺寸最小，最安全，最精确完整的单芯片控制器♦片上功率MOSFET-无外部FET♦电路占用面积<0.93in2♦回路高度<3mm♦温度稳定性为0.001°C♦集成精密积分器和斩波稳定运算放大器♦精确，独立的加热和冷却电流限制♦通过直接控制TEC电流消除浪涌♦可调节差分TEC电压限制♦低纹波和低噪声设计♦TEC电流监视器♦温度监控器♦过温和欠温警报♦双极性±3A输出电流（MAX1978）♦单极性+ 6A输出电流（MAX1979）订购信息* EP =裸焊盘。