MAX232芯片中文资料
MAX232CPE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 NetworksNext-Generation Device Features♦For Low-Voltage, Integrated ESD ApplicationsMAX3222E/MAX3232E/MAX3237E/MAX3241E/MAX3246E: +3.0V to +5.5V, Low-Power, Up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitors (MAX3246E Available in a UCSP™Package)♦For Low-Cost ApplicationsMAX221E: ±15kV ESD-Protected, +5V, 1µA,Single RS-232 Transceiver with AutoShutdown™MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers________________________________________________________________Maxim Integrated Products 1Selection Table19-4323; Rev 15; 1/06Power 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+52/240.047/0.33No —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 pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .Ordering InformationOrdering Information continued at end of data sheet.*Contact factory for dice specifications.AutoShutdown and UCSP are trademarks of Maxim Integrated Products, Inc.M A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGS—MAX220/222/232A/233A/242/243ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243Note 1:For the MAX220, V+ and V- can have a maximum magnitude of 7V, but their absolute difference cannot exceed 13V.Note 2:Input voltage measured with T OUT in high-impedance state, SHDN or V CC = 0V.Note 3:Maximum reflow temperature for the MAX233A is +225°C.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 V+ (Note 1)..................................................(V CC - 0.3V) to +14V V- (Note 1).............................................................+0.3V to +14V Input VoltagesT IN ..............................................................-0.3V to (V CC - 0.3V)R IN (Except MAX220)........................................................±30V R IN (MAX220).....................................................................±25V T OUT (Except MAX220) (Note 2).......................................±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)..842mW18-Pin Plastic DIP (derate 11.11mW/°C above +70°C)..889mW 20-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, 10s) (Note 3)...................+300°CMAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________3Note 4:MAX243 R2OUT IN ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243 (continued)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 (kb/s)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 )ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243 (continued)(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.)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, 10s) (Note 4)...................+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.Note 4:Maximum reflow temperature for the MAX233/MAX235 is +225°C.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.)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 5).....................................................................±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,10s) (Note 6)....................+300°CNote 5:Input voltage measured with transmitter output in a high-impedance state, shutdown, or V CC = 0V.Note 6:Maximum reflow temperature for the MAX225/MAX245/MAX246/MAX247 is +225°C.MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________9Note 7: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/ReceiversFigure 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 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/ReceiversM 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 pullup resistors to V CC are built in (except for the MAX220). The pullup resistors force the outputs of unused drivers low because all drivers invert.The internal input pullup resistors typically source 12µA,except in shutdown mode where the pullups 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 pullup resistors to force the outputs 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/ReceiversTable 2. Three-State Control of ReceiversMAX220–MAX249Drivers/Receiversnominal 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 20kb/s.__________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/Receivers。
MAX232中文资料
MAX232资料简介MAX232芯片是美信公司专门为电脑的RS-232标准串口设计的单电源电平转换芯片，使用+5v单电源供电。
一、引脚介绍：第一部分：是电荷泵电路。
由1、2、3、4、5、6脚和4只电容构成。
功能是产生+12v和-12v两个电源，提供给RS-232串口电平的需要。
第二部分：是数据转换通道。
由7、8、9、10、11、12、13、14脚构成两个数据通道。
其中13脚(R1IN)、12脚(R1OUT)、11脚(T1IN)、14脚(T1OUT)为第一数据通道。
8脚(R2IN)、9脚(R2OUT)、10脚(T2IN)、7脚(T2OUT)为第二数据通道。
TTL/CMOS数据从T1IN、T2IN输入转换成RS-232数据从T1OUT、T2OUT送到电脑DB9插头；DB9插头的RS-232数据从R1IN、R2IN输入转换成TTL/CMOS数据后从R1OUT、R2OUT输出。
第三部分：是供电。
15脚GND、16脚VCC(+5v)。
二、主要特点：1、符合所有的RS-232C技术标准2、只需要单一+5V电源供电3、片载电荷泵具有升压、电压极性反转能力，能够产生+10V和-10V电压V+、V-4、功耗低，典型供电电流5mA5、内部集成2个RS-232C驱动器6、内部集成两个RS-232C接收器下图为MX232双串口的连接图，可以分别接单片机的串行通信口或者实验板的其它串行通信接口：三、max232应用电路，注意电容接法。
232是电荷泵芯片，可以完成两路TTL/RS-232电平的转换，它的的9、10、11、12引脚是TTL电平端，用来连接单片机的。
MAX232心得MAX232DIP16封装现主要有这些型号：MAX232CPE、MAX232EPE。
下面对MAX232的型号标识进行解析：①MAX232后缀第一个字母，表示应用级别。
“C”：商业级；“E”：工业级。
例：MAX232CPE：商业级；②MAX232后缀第二个字母，表示封装。
max232 (2)
Max232介绍Max232是一款集成电路(IC)，通常用于RS-232串行通信接口和微控制器(或其他数字设备)之间的电平转换。
RS-232是一种常见的串行通信标准，用于在不同设备之间传输数据。
然而，RS-232使用的电平范围与微控制器和其他数字设备的标准电平范围不同。
因此，需要一个电平转换器来实现两者之间的通信。
Max232解决了这个问题。
它由内部逻辑电路和电容器组成，可以将低电平转换为高电平，反之亦然，以实现RS-232和微控制器之间的电平转换。
架构Max232由两个逻辑电路组成，每个逻辑电路接受一个RS-232信号和一个电源电压。
一般来说，Max232 IC的供电电压在3.0V到5.5V之间，因此它适用于各种电源电压条件下的应用。
在逻辑电路中，Max232使用了电容器来产生负电压。
通过连接外部电容器，IC可以从正电压源产生一个负电压源。
这个负电压用于将RS-232信号提升到正常的RS-232电平范围。
引脚配置Max232具有16个引脚，按功能可以分成四个组：Vcc和GND•Vcc引脚提供IC的电源电压，通常在3.0V到5.5V之间。
•GND引脚用于接地。
RS-232输入和输出•T1IN和T2OUT是Max232的发送线路。
•R2IN和R1OUT是Max232的接收线路。
电容器连接引脚•C1+和C1-是电容器C1的连接引脚。
•C2+和C2-是电容器C2的连接引脚。
使用方法使用Max232进行电平转换非常简单。
以下是基本的使用步骤：1.将RS-232信号连接到T1IN引脚。
这是需要转换为微控制器可识别电平的信号。
2.将T2OUT引脚连接到微控制器的接收引脚。
这将是接收Max232转换后的信号。
3.链接电容器C1和C2到C1+、C1-和C2+、C2-引脚，以供电和产生负电压。
4.连接Vcc和GND引脚到适当的电源和地线。
完成上述步骤后，Max232将执行电平转换并允许RS-232设备与微控制器进行通信。
MAX232中文
+5V供电、多通道RS-232驱动器、接收器详细介绍MAX220-MAX249包括4个部分:双路电荷泵DC-DC电压转换器、RS-232驱动器、RS-232接收器，以及接收器与发送器使能控制输入。
双路电荷泵电压转换器MAX220-MAX249内部有两个电荷泵，将+5V转换为+10V（空载），为RS-232驱动器提供工作电压。
第一个转换器利用电容C1将+5V输入加倍，得到V+输出端C3上的+10V；第二个转换器利用电容C2将+10V转换为V-输出端C4上的-10V。
可以从+10V（V+）和-10V（V-）输出端获取少量的电源功率，为外部电路供电；但MAX225与MAX245- MAX247例外，因为它们不提供这些引脚，V+与V-未经稳压，所以输出电压会随负载电流的增大而下降。
当V+、V-为外部电路提供电流时，注意不要因为所加载的原因使V+、V-低于EIA/TIA-232E驱动端输出电压最小值+5V的限制。
使用MAX2222、MAX225、MAX230、MAX235、MAX236、MAX240、MAX241以及MAX245- MAX249上的关断功能时，应避免V+与V-为外部电路供电。
这些器件关断时，V-降至0V，V+降至+5V。
对于那些能够将+10V外部电源提供到V+引脚（而不是使用内部电荷泵来产生+10V）的应用，一定不要安装电容C1，并且必须将SHDN引脚连接至Vcc，这是应为在关断模式下V+被内部连接到Vcc。
RS-232驱动器如果负载是标称值为5KΩ的RS-232接收器，并且Vcc=+5V时，驱动器输出电压摆幅的典型值为+8V。
输出摆幅确保符合EIA/TIA-232E和V.28规范，该规范要求在最糟糕的情况下能够满足+5V驱动器输出电压最小值的要求，其中包括3KΩ的负载电阻最小值、Vcc=+4.5V以及最高工作温度。
空载是驱动器输出电压范围是（V+-1.3V）至（V-+0.5V）.输入门限兼容与TTL和COMS逻辑。
Get清风40 RS232标准串口设计的单电源电平转换芯片MAX232中文资料及应用
40 RS232标准串口设计的单电源电平转换芯片_MAX232_中文资料及应用max232中文资料及应用该产品是由德州仪器公司〔TI〕推出的一款兼容RS232标准的芯片。
由于电脑串口rs232电平是-10v +10 v，而一般的单片机应用系统的信号电压是ttl电平0 +5v,max232就是用来进行电平转换的,该器件包含2驱动器、2接收器和一个电压发生器电路提供TIA/EIA-232-F电平。
该器件符合TIA/EIA-232-F标准，每一个接收器将TIA/EIA-232-F电平转换成5-V TTL/CMOS电平。
每一个发送器将TTL/CMOS电平转换成TIA/EIA-232-F电平。
主要特点1、单5V电源工作2、 LinBiCMOSTM工艺技术3、两个驱动器及两个接收器4、±30V输入电平5、低电源电流：典型值是8mA7、ESD保护大于MIL-STD-883〔方法3015〕标准的2000V下列图为MX232双串口的连接图，可以分别接单片机的串行通信口或者实验板的其它串行通信接口：三.max232应用电路，注意电容接法。
232是电荷泵芯片，可以完成两路TTL/RS-232电平的转换，它的的9、10、11、12引脚是TTL电平端，用来连接单片机的。
制作at89s51单片机器编程器的电路图MAX232获得正负电源的另一种方法在单片机控制系统中，我们时常要用到数/模〔D/A〕或者模/数(A/D)变换以及其它的模拟接口电路，这里面要经常用到正负电源，例如： 9V,-9V; 12V,-12V.这些电源仅仅作为数字和模拟控制转换接口部件的小功率电源。
在控制板上，我们有的只是5V电源，可又有很多方法获得非5V电源。
1.外接；2.DC-DC变换......在这里我介绍一块大家常用的芯片：MAX232. MAX232是TTL --RS232电平转换的典型芯片，按照芯片的推荐电路，取振荡电容为uF的时候，假设输入为5V,输出可以到达-14V左右，输入为0V ,输出可以到达14V,在扇出电流为20mA的时候，处处电压可以稳定在 12V和-12V.因此，在功耗不是很大的情况下，可以将MAX232的输出信号经稳压块后作电源使用。
max232资料
MAX232CPE是MAX232的子型号！MAX232CPE是专为RS-232和V.28通信接口设计的收发器，尤其是±12V供压无法实现的情况。
型号标识/参数
MAX232CPE的型号标识和参数如下表所示：
MAX232CPE型号标识
MAX
MAXIM品牌标识
232
基本型号
C
温度等级，商业级(1)
P
封装类型，PDIP(2)
E
引脚数，16PIN
MAX232CPE参数特性
Vcc (V)
5
传输速率（kbps）
120
外部电容大小(uF)
1
温度等级
0℃至70℃
(1)C=商业级（0℃至70℃），E=工业级（-40℃至80℃）
M=军工级（-55℃至125℃）
(2)P=PDIP16,S=SOIC16窄体,W=SOIC16宽体,U=TSSOP16
价格表标定的价格为零售价，如需批量采购，欢迎来电咨询洽谈！
MAX232CPE的文字介绍及图片仅供参考，所有信息均以官方最新PDF及实物为准！
J=CERDIP16,L=LCC20
封装信息
MAX232CPE的封装为：
类型：PDIP
引脚：16
标准：JEDEC MS-001 AA
体宽：300 mil
引脚间距：100 mil / 2.规格为：
·类型：Tube（管装）
每管：25pcs
每标准包：40管，共1,000pcs
MAX232中文资料_数据手册_参数
max232是什么芯片
max232是什么芯片MAX232是一种串口转换芯片，用于将TTL（逻辑电平）信号转换成RS232（标准电平）信号。
它广泛应用于计算机硬件通讯领域，如串口通信、电话线调制解调、计算机接口等。
MAX232芯片由Maxim公司设计和生产，是一款双路驱动、双路接收的RS232接口芯片。
它的主要功能是将计算机与其他外设之间的信息转换，以便于计算机与其他设备进行串口通信。
MAX232芯片的主要特点有以下几个方面：1. 低成本：MAX232芯片采用集成电路设计，可以用较低的成本生产出大量的芯片。
2. 双路驱动：MAX232芯片具备双路驱动功能，可以同时驱动两个接收器和两个发射器，适用于双向通信。
3. 兼容性强：MAX232芯片能够将计算机的TTL电平信号转换成RS232标准电平信号，并且在芯片内部进行了自动电平转换，使得计算机与其他设备的通信更加稳定。
4. 外围元件简单：MAX232芯片只需要一些简单的电容器和电阻器作为外围元件，不需要额外的电源供给，减少了系统设计的复杂性。
5. 低功耗：MAX232芯片的功耗较低，适合于在嵌入式系统中使用。
MAX232芯片的工作原理比较简单。
它通过四个电容器和四个电阻器组成一个电压倍增电路，从而将TTL电平（通常为0V和5V）转换为RS232电平（通常为-12V和12V）。
同时，它还能够将RS232电平转换为TTL电平，实现数据的双向传输。
在计算机与外部设备通信时，MAX232芯片的引脚连接如下：1. 引脚2（T1IN）和引脚3（T1OUT）分别连接到计算机的发送线和接收线，用于传输TTL电平信号。
2. 引脚14（R1OUT）和引脚13（R1IN）分别连接到计算机的接收线和发送线，用于接收RS232电平信号。
3. 引脚6（VCC）和引脚11（GND）连接到系统的电源供给线和地线。
4. 引脚7（C1+）和引脚8（C1-）以及引脚5（C2+）和引脚4（C2-）分别连接到对应的电容器和电阻器。
MAX232详细中文总结
MAX232详细资料总结max232 是用来做电平转换的,标准rs232 电平很高，达正负15V.常用的TTL 电平最高5V。
相互连接的话，必须进行电平转换！由于电脑串口输出电压高达12V，直接与单片机连接会烧坏芯片。
所以用MAX232来进行电平转换。
MAX232芯片采用单+5V电源供电，仅需几个外接电容即可完成从TTL到RS232电平的转换，共两路。
其中13脚（R1IN）、12脚（R1OUT）、11脚（T1IN）、14脚（T1OUT）为第一数据通道。
8脚（R2IN）、9脚（R2OUT）、10脚（T2IN）、7脚（T2OUT）为第二数据通道。
TTL/CMOS数据从T1IN、T2IN输入转换成RS-232数据从T1OUT、T2OUT送到电脑DP9插头；DP9插头的RS-232数据从R1IN、R2IN输入转换成TTL/CMOS数据后从R1OUT、R2OUT输出。
MAX232通信电路图单片机中的UART和电脑串口RS232的区别仅在于电平的不同,电脑串口采用232电平,而单片机UART则采用TTL电平,如果不进行电平转换,单片机跟电脑串口就不能进行直接通信,RS232是UART的一种就意味着通信协议的格式是一样的,只要电平统一了,两者之间就可以直接通信,于是乎应用了MAX232这一芯片，MAX232对两者之间通信的数据没有任何作用,仅仅是中介而已,而其只是负责将两者之间的电平进行统一,使两者之间没有通信障碍。
1 TXD 输出数据输出到串口2 DTR_N 输出数据终端准备好，低电平有效3 RST_N 输出发送请求，低电平有效4 VDD_325 电源RS232电源3.3V5 RXD 输入串口数据输入6 RI_N 输入/输出串行端口（环指示器）7 GND 电源接地8 VDD 输入/输出电源9 DSR_N 输入/输出串行端口（数据集就绪）10 DCD_N 输入/输出串行端口（数据载波检测）11 CTS_N 输入/输出串行端口（清除发送）12 SHTD_N 输出控制RS232收发器关机13 EE_CLK 输入/输出串行EEPROM时钟14 EE_DATA 输入/输出串行EEPROM数据15 DP 输入/输出USB端口D+信号16 DM 输入/输出USB端口D-信号17 VO_33常规3.3V电源输出18 GND接地19 RESET复位引脚20 VDD_5 电源USB端口的5V电压电源21 GND接地22 GP0 输入/输出通用I/O引脚023 GP1 输入/输出通用I/O引脚124 VDD_PLL模拟正5v锁相环25 GND_PLL模拟地锁相环26 PLL_TEST 输入PLL锁相环测试模式控制27 OSC1 输入晶体振荡器输入28 OSC2 输入/输出晶体振荡器输出PL2303 是Prolific 公司生产的一种高度集成的RS232-USB 接口转换器，可提供一个RS232 全双工异步串行通信装置与USB 功能接口便利联接的解决方案。
max232芯片
max232芯片MAX232是一款常见的RS-232级别转换芯片，用于将RS-232级别的信号转换为TTL/CMOS级别的信号，从而实现RS-232串口与微控制器或其他逻辑电路的连接。
MAX232芯片由美国公司Maxim IntegratedProducts研发生产，广泛应用于电子设备中的串口通信。
MAX232芯片有多个型号，如MAX232、MAX232E等，不同型号之间参数可能存在差异，但基本原理和功能大致相同。
MAX232芯片包括两个发送器和两个接收器，可为两条RS-232串口提供TTL/CMOS级别的信号转换。
MAX232芯片的两个发送器使用外部电容来实现电压倍增功能，RS-232的电压范围是15V到-15V，而TTL/CMOS电平一般为5V到0V。
发送器将TTL/CMOS的逻辑电平转换为RS-232的正负电平，通过电容产生高于5V的电压，从而实现电平转换。
MAX232芯片的两个接收器使用电阻分压电路将RS-232的电压范围转换为TTL/CMOS电平范围。
接收器通过电阻分压将RS-232的正负电平转换为0V到5V的TTL/CMOS电平，从而实现电平转换。
MAX232芯片还包括一个内部的电压稳压器，用于实现5V的稳定电源供电。
在使用MAX232芯片时，只需提供外部一个较高的电压，如V+可以为5V到15V，然后芯片内部的电压稳压器会将该电压稳定为5V用于芯片内部的电路工作。
MAX232芯片常用于将RS-232接口的电平转换为TTL/CMOS 电平，以实现串口通信。
比如，它可以将计算机的RS-232串口信号转换为TTL/CMOS电平，通过与单片机连接，实现计算机与单片机的通信。
同时，它还可以用于其他类型电子设备的串口扩展和通信。
MAX232芯片结构简单、应用广泛，并且有较低的成本，因此在许多电子设备中被广泛使用。
它提供了一种简单可靠的RS-232与TTL/CMOS电平之间的转换方法，方便了串口设备之间的连接与通信。
MEMORY存储芯片MAX232AESE+T中文规格书
Integrated | 10Shutdown and Enable Control (MAX205E/MAX206E/MAX211E/MAX213E/MAX241E)In shutdown mode, the charge pumps are turned off,V+ is pulled down to V CC , V- is pulled to ground, and the transmitter outputs are disabled. This reduces sup-ply current typically to 1µA (15µA for the MAX213E).The time required to exit shutdown is under 1ms, asshown in Figure 5.Receivers All MAX213E receivers, except R4 and R5, are put into a high-impedance state in shutdown mode (see Tables 1a and 1b). The MAX213E’s R4 and R5 receivers still function in shutdown mode. These two awake-in-shut-down receivers can monitor external activity while main-taining minimal power consumption.The enable control is used to put the receiver outputs into a high-impedance state, to allow wire-OR connection of two EIA/TIA-232E ports (or ports of different types) at the UART. It has no effect on the RS-232 drivers or the charge pumps.Note: The enable c ontrol pin is ac tive low for the MAX211E/MAX241E (EN ), but is ac tive high for theMAX213E (EN). The shutdown control pin is active highFigure 4. Charge-Pump DiagramWhen in low-power shutdown mode, the MAX205E/MAX206E/MAX211E/MAX213E/MAX241E driver outputsare turned off and draw only leakage currents—even ifthey are back-driven with voltages between 0V and12V. Below -0.5V in shutdown, the transmitter output isdiode-clamped to ground with a 1k Ω series imped-ance.RS-232 ReceiversThe receivers convert the RS-232 signals to CMOS-logicoutput levels. The guaranteed 0.8V and 2.4V receiverinput thresholds are significantly tighter than the ±3Vthresholds required by the EIA/TIA-232E specification.This allows the receiver inputs to respond to TTL/CMOS-logic levels, as well as RS-232 levels.The guaranteed 0.8V input low threshold ensures thatreceivers shorted to ground have a logic 1 output. The5k Ω input resistance to ground ensures that a receiverwith its input left open will also have a logic 1 output.Receiver inputs have approximately 0.5V hysteresis.This provides clean output transitions, even with slowrise/fall-time signals with moderate amounts of noiseand ringing.In shutdown, the MAX213E’s R4 and R5 receivers haveno hysteresis.找MEMORY 、二三极管上美光存储Integrated | 13MAX202E–MAX213E,MAX232E/MAX241E ±15kV ESD-Protected, 5V RS-232 Transceivers outputs. Therefore,after PC board assembly,theMachine Model is less relevant to I/O ports.Applications InformationCapacitor SelectionThe capacitor type used for C1–C4 is not critical forproper operation. The MAX202E, MAX206–MAX208E,MAX211E, and MAX213E require 0.1µF capacitors,and the MAX232E and MAX241E require 1µF capaci-tors, although in all cases capacitors up to 10µF canbe used without harm. Ceramic, aluminum-electrolytic,or tantalum capacitors are suggested for the 1µFcapacitors, and ceramic dielectrics are suggested forthe 0.1µF capacitors. When using the minimum recom-mended capacitor values, make sure the capacitancevalue does not degrade excessively as the operatingtemperature varies. If in doubt, use capacitors with alarger (e.g., 2x) nominal value. The capacitors’ effec-tive series resistance (ESR), which usually rises at lowtemperatures, influences the amount of ripple on V+and V-.Use larger capacitors (up to 10µF) to reduce the outputimpedance at V+ and V-. This can be useful when“stealing” power from V+ or from V-. The MAX203E andMAX205E have internal charge-pump capacitors.Bypass V CC to ground with at least 0.1µF. In applica-tions sensitive to power-supply noise generated by the charge pumps, decouple V CC to ground with a capaci-tor the same size as (or larger than) the charge-pump capacitors (C1–C4).V+ and V- as Power Supplies A small amount of power can be drawn from V+ and V-,although this will reduce both driver output swing and noise margins. Increasing the value of the charge-pump capacitors (up to 10µF ) helps maintain performance when power is drawn from V+ or V-.Driving Multiple Receivers Each transmitter is designed to drive a single receiver.Transmitters can be paralleled to drive multiple receivers.Driver Outputs when Exiting Shutdown The driver outputs display no ringing or undesirable transients as they come out of shutdown.High Data Rates These transceivers maintain the RS-232 ±5.0V mini-mum driver output voltages at data rates of over 120kbps. F or data rates above 120kbps, refer to the Transmitter Output Voltage vs. Load Capacitance graphs in the Typical Operating Characteristics .Communication at these high rates is easier if the capacitive loads on the transmitters are small; i.e.,short cables are best.Table 2. Summary of EIA/TIA-232E, V.28 Specifications PARAMETERCONDITIONS EIA/TIA-232E, V.28 SPECIFICA-TIONS 0 Level3k Ωto 7k Ωload +5V to +15V Data Rate 3k Ω≤R L ≤7k Ω, C L ≤2500pFUp to 20kbps +3V to +15V Instantaneous Slew Rate, Max 3k Ω≤R L ≤7k Ω, C L ≤2500pF 30V/µsDriver Output Short-Circuit Current, Max 100mATransition Rate on Driver Output V.281ms or 3% of the period Driver Output Resistance-2V < V OUT < +2V 300ΩEIA/TIA-232E4% of the period Driver Output Level, Max No load±25V Driver Output Voltage 3k Ωto 7k Ωload-5V to -15V 0 Level1 Level 1 Level Receiver Input Level ±25VReceiver Input Voltage -3V to -15V。
max232中文资料max232cpe中文资料
max232中文资料max232cpe中文资料max232中文资料一:MAX232资料总结Max232总结为什么会想到总结max232呢？因为又一次我在整理芯片资料，想对芯片进分类时，竟然不知道要把max232归到哪一类。
后来自己查了一下资料，原来max232是进行电平转换的，于是把它归类到电平转换芯片内。
为什么是电平转换芯片呢？这就要明白它的工作范围？它是工作在电脑和单片机之间的。
这就存在着两种不同的电平，一个是TTL电平，一个是RS232电平。
我们都知道单片机是TTL电平，其逻辑1代表5V，逻辑0电表0V，而RS232电平逻辑1是-3V~-15V，逻辑0是+3V~+15V。
所以可以把它归类到电平转换芯片类。
下面总结一下，max232的电容的种类和作用。
使用的电容会因为max232不同的种类而有区别。
下面讲一下这些电容的作用。
因为232和TTL的电压是有很大的差别的。
下面这段话为网上复制的：232的工作电平高于收发器的工作电压，需要进行电压抬升。
MAX232所采用的方法是利用电荷泵（charge pump）抬升电压，因此需要这4个储能电容。
至于Vcc和GND之间的10uF电容器则是为了防止4路电荷泵的电源变化影响到前端。
此处其实加一片0.1uF更好。
怎么来理解这段话呢？从上图中可以看到，RS232电平到TTL电平传输时，下接了5千欧的电阻，这是为了降压。
那TTL到RS232呢？怎么样由5V升到15V呢？这就要使用电压泵了。
具体什么是电压泵我也没仔细查，但见名知意，就是提升电压的。
从上图中看到TTL到RS232传输时，5V的电压经过400千欧的电阻与其相连。
这最多也就升到5V，显然离15V还是有差距的。
这就发挥了232电容上4个电容的作用。
它的作用是储能、升压。
max232中文资料二:MAX232 与__ 外部电路电容MAX232 与__ 外部电路电容分类：嵌入式学习STM32/STM82011-11-26 09:581204人阅读评论(0)收藏举报扩展测试工作io 这几天开始忙于调试我们自己的STM32主板，2.4G RF模块已经调试成功，然后接着调试串口，也就是如此，问题来了。
MAX232是什么？
MAX232 是什么？
MAX232 芯片是美信公司专门为电脑的RS-232 标准串口设计的接口电路,使用+5v 单电源供电。
它的内部结构基本可分三个部分;第一部分是电荷泵电路。
由1、2、3、4、5、6 脚和4 只电容构成。
功能是产生+12v 和-12v 两个电源，提供给RS-232 串口电平的需要。
第二部分是数据转换通道。
由7、8、9、10、11、12、13、14 脚构成两个数据通道。
其中13 脚
(R1IN)、12 脚(R1OUT)、11 脚(T1IN)、14 脚(T1OUT)为第一数据通道。
8 脚(R2IN)、9 脚(R2OUT)、10 脚(T2IN)、7 脚(T2OUT)为第二数据通道。
TTL/CMOS 数据从T1IN、T2IN 输入转换成RS-232 数据从T1OUT、
T2OUT 送到电脑DP9 插头;DP9 插头的RS-232 数据从R1IN、R2IN 输入转换成TTL/CMOS 数据后从R1OUT、R2OUT 输出。
而我们用只需一个通道就行啦。
所以一通道的11、12、13、14 脚就全空脚啦。
我们只用了第二通道的4 只脚。
` 第三部分就是供电啦。
MAX232引脚图功能应用电路 MAX232中文资料PDF数据手册下载
MAX232引脚图功能应用电路MAX232中文资料PDF数据手册下载MAX232 - 通信接口驱动器介绍
简介：
+5V供电、多通道RS-232驱动器/接收器
描述：
MAX220MAX249系列线驱动器/接收器，专为EIA/TIA-232E以及V.28/V.24通信接口设计，尤其是无法提供12V电源的应用。
这些器件特别适合电池供电系统，这是由于其低功耗关断模式可以将功耗减小到5W以内。
MAX225、MAX233、MAX235以及MAX245/MAX246/MAX247不需要外部元件，推荐用于印刷电路板面积有限的应用。
应用：
便携式计算机
低功耗调制解调器
接口转换
电池供电RS-232系统
多点RS-232网络
关键特性
对于低电压、集成ESD应用
MAX3222E/MAX3232E/MAX3237E/MAX3241E/MAX3246E：+3.0V至+5.5V、低功耗、最高1Mbps、真正的RS-232收发器，使用4个0.1F外部电容(MAX3246E提供UCSP封装) 对于低成本应用MAX221E：15kV ESD保护、+5V、1A、单路RS-232收发器，带AutoShutdown
想了解更多关于通信接口驱动器MAX232 相关资料(MAX220MAX249系列)，请=点击此处到MAX232 资料页面下载。
max232
MAX232芯片简介MAX232芯片是美信公司专门为电脑的RS-232标准串口设计的单电源电平转换芯片,使用+5v单电源供电。
编辑本段图片编辑本段引脚介绍第一部分是电荷泵电路。
由1、2、3、4、5、6脚和4只电容构成。
功能是产生+12v和-12v两个电源，提供给RS-232串口电平的需要。
第二部分是数据转换通道。
由7、8、9、10、11、12、13、14脚构成两个数据通道。
其中13脚（R1IN）、12脚（R1OUT）、11脚（T1IN）、14脚（T1OUT）为第一数据通道。
8脚（R2IN）、9脚（R2OUT）、10脚（T2IN）、7脚（T2OUT）为第二数据通道。
TTL/CMOS数据从T1IN、T2IN输入转换成RS-232数据从T1OUT、T2OUT送到电脑DB9插头；DB9插头的RS-232数据从R1IN、R2IN输入转换成TTL/CMOS数据后从R1OUT、R2OUT输出。
第三部分是供电。
15脚GND、16脚VCC（+5v）。
编辑本段主要特点1、符合所有的RS-232C技术标准2、只需要单一+5V电源供电3、片载电荷泵具有升压、电压极性反转能力，能够产生+10V和-10V电压V+、V-4、功耗低，典型供电电流5mA5、内部集成2个RS-232C驱动器6、内部集成两个RS-232C 接收器MAX232 一般说明：该max220 - max249家庭的线路驱动器/接收器是打算为所有eia/tia-232e和v.28/v.24通信筹措接口，特别是应用±12V的是无法使用。
这些零件是特别有用，在电池供电系统tems ，因为他们的低功耗停机模式，减少功耗要小于5μ瓦特该max225，max233，max235，max245/max246/max247使用无需外部元件，并建议应用- 阳离子如印刷电路板空间是至关重要的。
MAX232 特征：.优于双极.经营从单一的5伏供电（5V和12v-max231/max239 ）.低功耗接收模式，在关机（max223/max242 ）.满足所有eia/tia-232e和v.28规格.多个驱动器和接收器.3态驱动器和接收器输出开放式在线检测（max243 ）MAX232 概述MAX232（MAX220–MAX249系列）是专为RS-232和V.28通信接口设计的收发器，尤其是±12V供压无法实现的情况。
MAX232EPE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 NetworksNext-Generation Device Features♦For Low-Voltage, Integrated ESD ApplicationsMAX3222E/MAX3232E/MAX3237E/MAX3241E/MAX3246E: +3.0V to +5.5V, Low-Power, Up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitors (MAX3246E Available in a UCSP™Package)♦For Low-Cost ApplicationsMAX221E: ±15kV ESD-Protected, +5V, 1µA,Single RS-232 Transceiver with AutoShutdown™MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers________________________________________________________________Maxim Integrated Products 1Selection Table19-4323; Rev 15; 1/06Power 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+52/240.047/0.33No —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 pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .Ordering InformationOrdering Information continued at end of data sheet.*Contact factory for dice specifications.AutoShutdown and UCSP are trademarks of Maxim Integrated Products, Inc.M A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGS—MAX220/222/232A/233A/242/243ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243Note 1:For the MAX220, V+ and V- can have a maximum magnitude of 7V, but their absolute difference cannot exceed 13V.Note 2:Input voltage measured with T OUT in high-impedance state, SHDN or V CC = 0V.Note 3:Maximum reflow temperature for the MAX233A is +225°C.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 V+ (Note 1)..................................................(V CC - 0.3V) to +14V V- (Note 1).............................................................+0.3V to +14V Input VoltagesT IN ..............................................................-0.3V to (V CC - 0.3V)R IN (Except MAX220)........................................................±30V R IN (MAX220).....................................................................±25V T OUT (Except MAX220) (Note 2).......................................±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)..842mW18-Pin Plastic DIP (derate 11.11mW/°C above +70°C)..889mW 20-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, 10s) (Note 3)...................+300°CMAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________3Note 4:MAX243 R2OUT IN ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243 (continued)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 (kb/s)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 )ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243 (continued)(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.)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, 10s) (Note 4)...................+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.Note 4:Maximum reflow temperature for the MAX233/MAX235 is +225°C.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.)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 5).....................................................................±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,10s) (Note 6)....................+300°CNote 5:Input voltage measured with transmitter output in a high-impedance state, shutdown, or V CC = 0V.Note 6:Maximum reflow temperature for the MAX225/MAX245/MAX246/MAX247 is +225°C.MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________9Note 7: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/ReceiversFigure 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 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/ReceiversM 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 pullup resistors to V CC are built in (except for the MAX220). The pullup resistors force the outputs of unused drivers low because all drivers invert.The internal input pullup resistors typically source 12µA,except in shutdown mode where the pullups 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 pullup resistors to force the outputs 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/ReceiversTable 2. Three-State Control of ReceiversMAX220–MAX249Drivers/Receiversnominal 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 20kb/s.__________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/Receivers。
MAX232中文资料(官方版)
________________________________ 应用
便携式计算机 低功耗调制解调器 接口转换 电池供电 RS-232 系统 多点 RS-232 网络
_____________________________ 定购信息
PART MAX220CPE MAX220CSE MAX220CWE MAX220C/D MAX220EPE MAX220ESE MAX220EWE MAX220EJE MAX220MJE TEMP RANGE 0°C to +70°C 0°C to +70°C 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -55°C to +125°C PIN-PACKAGE 16 Plastic DIP 16 Narrow SO 16 Wide SO Dice* 16 Plastic DIP 16 Narrow SO 16 Wide SO 16 CERDIP 16 CERDIP
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+5V 供电、多通道 RS-232 驱动器/接收器 MAX220–MAX249
ABSOLUTE MAXIMUM RATINGS—MAX220/222/232A/233A/242/243
Supply Voltage (VCC) ...............................................-0.3V to +6V V+ (Note 1) ..................................................(VCC - 0.3V) to +14V V- (Note 1) .............................................................+0.3V to +14V Input Voltages TIN..............................................................-0.3V to (VCC - 0.3V) RIN (Except MAX220) ........................................................±30V RIN (MAX220).....................................................................±25V TOUT (Except MAX220) (Note 2) .......................................±15V TOUT (MAX220)...............................................................±13.2V Output Voltages TOUT ...................................................................................±15V ROUT .........................................................-0.3V to (VCC + 0.3V) Driver/Receiver Output Short Circuited to GND.........Continuous Continuous Power Dissipation (TA = +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)..889mW 20-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 Ranges MAX2_ _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, 10s) (Note 3) ...................+300°C
MAX232ACSE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 NetworksNext-Generation Device Features♦For Low-Voltage, Integrated ESD ApplicationsMAX3222E/MAX3232E/MAX3237E/MAX3241E/MAX3246E: +3.0V to +5.5V, Low-Power, Up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitors (MAX3246E Available in a UCSP™Package)♦For Low-Cost ApplicationsMAX221E: ±15kV ESD-Protected, +5V, 1µA,Single RS-232 Transceiver with AutoShutdown™MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers________________________________________________________________Maxim Integrated Products 1Selection Table19-4323; Rev 15; 1/06Power 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+52/240.047/0.33No —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 pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .Ordering InformationOrdering Information continued at end of data sheet.*Contact factory for dice specifications.AutoShutdown and UCSP are trademarks of Maxim Integrated Products, Inc.M A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGS—MAX220/222/232A/233A/242/243ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243Note 1:For the MAX220, V+ and V- can have a maximum magnitude of 7V, but their absolute difference cannot exceed 13V.Note 2:Input voltage measured with T OUT in high-impedance state, SHDN or V CC = 0V.Note 3:Maximum reflow temperature for the MAX233A is +225°C.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 V+ (Note 1)..................................................(V CC - 0.3V) to +14V V- (Note 1).............................................................+0.3V to +14V Input VoltagesT IN ..............................................................-0.3V to (V CC - 0.3V)R IN (Except MAX220)........................................................±30V R IN (MAX220).....................................................................±25V T OUT (Except MAX220) (Note 2).......................................±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)..842mW18-Pin Plastic DIP (derate 11.11mW/°C above +70°C)..889mW 20-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, 10s) (Note 3)...................+300°CMAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________3Note 4:MAX243 R2OUT IN ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243 (continued)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 (kb/s)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 )ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243 (continued)(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.)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, 10s) (Note 4)...................+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.Note 4:Maximum reflow temperature for the MAX233/MAX235 is +225°C.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.)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 5).....................................................................±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,10s) (Note 6)....................+300°CNote 5:Input voltage measured with transmitter output in a high-impedance state, shutdown, or V CC = 0V.Note 6:Maximum reflow temperature for the MAX225/MAX245/MAX246/MAX247 is +225°C.MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________9Note 7: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/ReceiversFigure 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 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/ReceiversM 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 pullup resistors to V CC are built in (except for the MAX220). The pullup resistors force the outputs of unused drivers low because all drivers invert.The internal input pullup resistors typically source 12µA,except in shutdown mode where the pullups 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 pullup resistors to force the outputs 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/ReceiversTable 2. Three-State Control of ReceiversMAX220–MAX249Drivers/Receiversnominal 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 20kb/s.__________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/Receivers。
MAX232芯片介绍
MAX232芯片是美信公司专门为电脑的RS-232标准串口设计的单电源电平转换芯片,使用+5v单电源供电。
图2.3 MAX232芯片管脚图
引脚介绍：
第一部分是电荷泵电路。
由1、2、3、4、5、6脚和4只电容构成。
功能是产生+12v和-12v两个电源，提供给RS-232串口电平的需要。
第二部分是数据转换通道。
由7、8、9、10、11、12、13、14脚构成两个数据通道。
其中13脚（R1IN）、12脚（R1OUT）、11脚（T1IN）、14脚（T1OUT）为第一数据通道。
8脚（R2IN）、9脚（R2OUT）、10脚（T2IN）、7脚（T2OUT）为第二数据通道。
TTL/CMOS数据从T1IN、T2IN输入转换成RS-232数据从T1OUT、T2OUT送到电脑DB9插头；DB9插头的RS-232数据从R1IN、R2IN输入转换成TTL/CMOS数据后从R1OUT、R2OUT输出。
第三部分是供电。
15脚GND、16脚VCC（+5v）。
主要特点：
1、符合所有的RS-232C技术标准
2、只需要单一 +5V电源供电
3、片载电荷泵具有升压、电压极性反转能力，能够产生+10V和-10V电压V+、V-
4、功耗低，典型供电电流5mA
5、内部集成2个RS-232C驱动器
6、内部集成两个RS-232C接收器下图为MX232双串口的连接图，可以分别接单片机的串行通信口或者实验板的其它串行通信接口：
图2.4 RS-232接口图。
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#include<pic.h> //包含单片机内部资源预定义 __CONFIG(0x3F52); //4M 晶体 HS 振荡 /******************************************************************************* 延时 1MS 带参数(int)子程序 *******************************************************************************/ void delay (unsigned int time){ unsigned int a,b; for(a=0;a<time;a++){ for(b=0;b<88;b++); } }
//主程序 void main() { unsigned char string[]={0xBB,0xB6,0xD3,0xAD,0xB9,0xE2,0xC1,0xD9,0xC1,0xD6,0xBE,0xA9,0xBF,0xC6,0xBC,0xB C,0xD3,0xD0,0xCF,0xDE,0xB9,0xAB,0xCB,0xBE,0x0D,0x0A,0xB3,0xCC,0xD0,0xF2,0xA3,0xBA,0xD6, 0xD0,0xB9,0xFA,0x20,0x51,0x51,0x3A,0x35,0x37,0x33,0x31,0x39,0x32,0x39,0x35,0x34,0x0D,0x0A}; unsigned char i; TRISC7=1; TRISC6=0; SPBRG=25; //设置波特率为 9600BPS TXSTA=0X24; //使能串口发送，选择高速波特率 RCSTA=0X80; //使能串口工作，禁止接收 INTCON=0X00; while(1) { for(i=0;i<51;i++){ while(!TRMT){;} TXREG=string[i]; } delay(2000); } }
一.max232 资料简介 该产品是由德州仪器公司（TI）推出的一款兼容 RS232 标准的芯片。由于电脑串口 rs232 电平是10v +10v，而一般的单片机应用系统的信号电压是 ttl 电平 0 +5v,max232 就是用来进行电平转换的, 该器件包含 2 驱动器、2 接收器和一个电压发生器电路提供 TIA/EIA-232-F 电平。 该器件符合 TIA/EIA-232-F 标准，每一个接收器将 TIA/EIA-232-F 电平转换成 5-V TTL/CMOS 电 平。每一个发送器将 TTL/CMOS 电平转换成 TIA/EIA-232-F 电平。 主要特点 1、单 5V 电源工作 2、 LinBiCMOSTM 工艺技术 3、 两个驱动器及两个接收器 4、 ±30V 输入电平 5、低电源电流：典型值是 8mA 6、符合甚至优于 ANSI 标准 EIA/TIA-232-E 及 ITU 推荐标准 V.28 7、ESD 保护大于 MIL-STD-883（方 法 3015）标准的 2000V
有一种 hin232 芯片，与 max232 芯片比较的话，价格相对要便宜很多。
max232 引脚图
下图为 MX232 双串口的连接图，可以分别接单片机的串行通信口或者实验板的其它串行通信接 口：
此主题相关图片如下： 三.max232 应用电路，注意电容接法。 232 是电荷泵芯片，可以完成两路 TTL/RS-232 电平的转换，它的的 9、0、11、12 引脚是 TTL 电 平端，用来连接单片机的。
此主题相关图片如下： 制作 at89s51 单片机器编程器的电路图 此主题相关图片如下：
MAX232 获得正负电源的另一种方法 在单片机控制系统中，我们时常要用到数/模（D/A）或者模/ 数(A/D)变换以及其它的模拟接口电路，这里面要经常用到正负电源，例如： 9V,-9V; 12V,-12V.这 些电源仅仅作为数字和模拟控制转换接口部件的小功率电源。 在控制板上，我们有的只是 5V 电 源，可又有很多方法获得非 5V 电源。 1.外接；2.DC-DC 变换......在这里我介绍一块大家常用的芯 片：MAX232. MAX232 是 TTL--RS232 电平转换的典型芯片，按照芯片的推荐电路，取振荡电容为 uF 的时候，若输入为 5V,输出可以达到-14V 左右，输入为 0V ,输出可以达到 14V,在扇出电流为 20mA 的时候，处处电压可以稳定在 12V 和-12V.因此，在功耗不是很大的情况下，可以将 MAX232 的输出信号经稳压块后作电源使用。 我在网上搜索了一些 232 的例程，但用单片机向 PC 发数据的程序较少，所有自己无耐，写了该程 序用于测试芯片有没有正常工作，希望能给有需要的朋友带来点方便！