MAX485ESA
MAX485EEPA+中文资料
14-Pin Plastic DIP (derate 10.00mW/°C above +70°C) ..800mW 8-Pin SO (derate 5.88mW/°C above +70°C).................471mW 14-Pin SO (derate 8.33mW/°C above +70°C)...............667mW Operating Temperature Ranges MAX4_ _C_ _/MAX1487EC_ A .............................0°C to +70°C MAX4_ _E_ _/MAX1487EE_ A...........................-40°C to +85°C StorageБайду номын сангаасTemperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10sec) .............................+300°C
Receiver Output Voltage (RO)....................-0.5V to (VCC + 0.5V)
Continuous Power Dissipation (TA = +70°C)
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ....727mW
Ordering Information
PART MAX481ECPA MAX481ECSA MAX481EEPA MAX481EESA MAX483ECPA MAX483ECSA MAX483EEPA MAX483EESA
max485
PACKAGING INFORMATIONOrderable Device Status(1)PackageType PackageDrawingPins PackageQtyEco Plan(2)Lead/Ball Finish MSL Peak Temp(3)SN65LBC184D ACTIVE SOIC D875Green(RoHS&no Sb/Br)CU NIPDAU Level-1-260C-UNLIMSN65LBC184DG4ACTIVE SOIC D875Green(RoHS&no Sb/Br)CU NIPDAU Level-1-260C-UNLIMSN65LBC184DR ACTIVE SOIC D82500Green(RoHS&no Sb/Br)CU NIPDAU Level-1-260C-UNLIMSN65LBC184DRG4ACTIVE SOIC D82500Green(RoHS&no Sb/Br)CU NIPDAU Level-1-260C-UNLIMSN65LBC184P ACTIVE PDIP P850Pb-Free(RoHS)CU NIPDAU N/A for Pkg TypeSN65LBC184PE4ACTIVE PDIP P850Pb-Free(RoHS)CU NIPDAU N/A for Pkg TypeSN75LBC184D ACTIVE SOIC D875Green(RoHS&no Sb/Br)CU NIPDAU Level-1-260C-UNLIMSN75LBC184DG4ACTIVE SOIC D875Green(RoHS&no Sb/Br)CU NIPDAU Level-1-260C-UNLIMSN75LBC184DR ACTIVE SOIC D82500Green(RoHS&no Sb/Br)CU NIPDAU Level-1-260C-UNLIMSN75LBC184DRG4ACTIVE SOIC D82500Green(RoHS&no Sb/Br)CU NIPDAU Level-1-260C-UNLIMSN75LBC184P ACTIVE PDIP P850Pb-Free(RoHS)CU NIPDAU N/A for Pkg TypeSN75LBC184PE4ACTIVE PDIP P850Pb-Free(RoHS)CU NIPDAU N/A for Pkg Type(1)The marketing status values are defined as follows:ACTIVE:Product device recommended for new designs.LIFEBUY:TI has announced that the device will be discontinued,and a lifetime-buy period is in effect.NRND:Not recommended for new designs.Device is in production to support existing customers,but TI does not recommend using this part in a new design.PREVIEW:Device has been announced but is not in production.Samples may or may not be available.OBSOLETE:TI has discontinued the production of the device.(2)Eco Plan-The planned eco-friendly classification:Pb-Free(RoHS),Pb-Free(RoHS Exempt),or Green(RoHS&no Sb/Br)-please check /productcontent for the latest availability information and additional product content details.TBD:The Pb-Free/Green conversion plan has not been defined.Pb-Free(RoHS):TI's terms"Lead-Free"or"Pb-Free"mean semiconductor products that are compatible with the current RoHS requirements for all6substances,including the requirement that lead not exceed0.1%by weight in homogeneous materials.Where designed to be soldered at high temperatures,TI Pb-Free products are suitable for use in specified lead-free processes.Pb-Free(RoHS Exempt):This component has a RoHS exemption for either1)lead-based flip-chip solder bumps used between the die and package,or2)lead-based die adhesive used between the die and leadframe.The component is otherwise considered Pb-Free(RoHS compatible)as defined above.Green(RoHS&no Sb/Br):TI defines"Green"to mean Pb-Free(RoHS compatible),and free of Bromine(Br)and Antimony(Sb)based flame retardants(Br or Sb do not exceed0.1%by weight in homogeneous material)(3)MSL,Peak Temp.--The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications,and peak solder temperature.Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided.TI bases its knowledge and belief on information provided by third parties,and makes no representation or warranty as to the accuracy of such information.Efforts are underway to better integrate information from third parties.TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.TI and TI suppliers consider certain information to be proprietary,and thus CAS numbers and other limited information may not be available for release.In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s)at issue in this document sold by TI to Customer on an annual basis.IMPORTANT NOTICETexas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications,enhancements, improvements, and other changes to its products and services at any time and to discontinueany product or service without notice. Customers should obtain the latest relevant information before placingorders and should verify that such information is current and complete. All products are sold subject to TI’s termsand conditions of sale supplied at the time of order acknowledgment.TI warrants performance of its hardware products to the specifications applicable at the time of sale inaccordance with TI’s standard warranty. T esting and other quality control techniques are used to the extent TIdeems necessary to support this warranty. Except where mandated by government requirements, testing of allparameters of each product is not necessarily performed.TI assumes no liability for applications assistance or customer product design. Customers are responsible fortheir products and applications using TI components. T o minimize the risks associated with customer productsand applications, customers should provide adequate design and operating safeguards.TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right,copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or processin which TI products or services are used. Information published by TI regarding third-party products or servicesdoes not constitute a license from TI to use such products or services or a warranty or endorsement thereof.Use of such information may require a license from a third party under the patents or other intellectual propertyof the third party, or a license from TI under the patents or other intellectual property of TI.Reproduction of information in TI data books or data sheets is permissible only if reproduction is withoutalteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproductionof this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable forsuch altered documentation.Resale of TI products or services with statements different from or beyond the parameters stated by TI for thatproduct or service voids all express and any implied warranties for the associated TI product or service andis an unfair and deceptive business practice. TI is not responsible or liable for any such statements.Following are URLs where you can obtain information on other Texas Instruments products and applicationsolutions:Products ApplicationsAmplifiers Audio /audioData Converters Automotive /automotiveDSP Broadband /broadbandInterface Digital Control /digitalcontrolLogic Military /militaryPower Mgmt Optical Networking /opticalnetworkMicrocontrollers Security /securityLow Power Wireless /lpw Telephony /telephonyVideo & Imaging /videoWireless /wirelessMailing Address:Texas InstrumentsPost Office Box 655303 Dallas, Texas 75265Copyright 2006, Texas Instruments Incorporated。
MEMORY存储芯片MAX485EEPA+中文规格书
Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers2MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487ABSOLUTE MAXIMUM RATINGSSupply Voltage (V CC ) (12V)Control Input Voltage (RE , DE)...................-0.5V to (V CC + 0.5V)Driver Input Voltage (DI).............................-0.5V to (V CC + 0.5V)Driver Output Voltage (A, B)...................................-8V to +12.5VReceiver Input Voltage (A, B).................................-8V to +12.5VReceiver Output Voltage (RO)....................-0.5V to (V CC + 0.5V)Continuous Power Dissipation (T A = +70°C)8-Pin Plastic DIP (derate 9.09mW/°C above +70°C)....727mW14-Pin Plastic DIP (derate 10.00mW/°C above +70°C)..800mW8-Pin SO (derate 5.88mW/°C above +70°C).................471mW 14-Pin SO (derate 8.33mW/°C above +70°C)...............667mW 8-Pin µMAX (derate 4.1mW/°C above +70°C)..............830mW 8-Pin CERDIP (derate 8.00mW/°C above +70°C).........640mW 14-Pin CERDIP (derate 9.09mW/°C above +70°C).......727mW Operating Temperature Ranges MAX4_ _C_ _/MAX1487C_ A...............................0°C to +70°C MAX4__E_ _/MAX1487E_ A.............................-40°C to +85°C MAX4__M_/MAX1487MJA.............................-55°C to +125°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering, 10sec).............................+300°C DC ELECTRICAL CHARACTERISTICS(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)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.V V IN = -7V V IN = 12V V IN = -7V V IN = 12V Input Current (A, B)I IN2V TH k Ω48-7V ≤V CM ≤12V, MAX487/MAX1487R INReceiver Input Resistance -7V ≤V CM ≤12V, all devices exceptMAX487/MAX1487R = 27Ω(RS-485), Figure 40.4V ≤V O ≤2.4VR = 50Ω(RS-422)I O = 4mA, V ID = -200mV I O = -4mA, V ID = 200mV V CM = 0V -7V ≤V CM ≤12V DE, DI, REDE, DI, RE MAX487/MAX1487,DE = 0V, V CC = 0V or 5.25VDE, DI, RE R = 27Ωor 50Ω, Figure 4R = 27Ωor 50Ω, Figure 4R = 27Ωor 50Ω, Figure 4DE = 0V;V CC = 0V or 5.25V,all devices exceptMAX487/MAX1487CONDITIONS k Ω12µA ±1I OZR Three-State (high impedance)Output Current at Receiver V 0.4V OL Receiver Output Low Voltage3.5V OH Receiver Output High VoltagemV 70ΔV TH Receiver Input HysteresisV -0.20.2Receiver Differential ThresholdVoltage-0.2mA 0.25mA -0.81.01.55V OD2Differential Driver Output(with load)V 2V 5V OD1Differential Driver Output (no load)µA ±2I IN1Input Current V 0.8V IL Input Low VoltageV 2.0V IH Input High VoltageV 0.2ΔV OD Change in Magnitude of DriverCommon-Mode Output Voltagefor Complementary Output StatesV 0.2ΔV OD Change in Magnitude of DriverDifferential Output Voltage forComplementary Output StatesV 3V OC Driver Common-Mode OutputVoltageUNITS MIN TYP MAX SYMBOL PARAMETERLow-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers7MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487______________________________________________________________Pin DescriptionFigure 1. MAX481/MAX483/MAX485/MAX487/MAX1487 Pin Configuration and Typical Operating Circuit。
公司(普飞诺)新推IC及替换型号
二：开关式降压IC可以应用于：蓄电池供电玩具，工业控制器，仪器仪表，医疗设备，安防，电动车控 制器，LED照明灯，家用电器控制板，办公设备等。
三：通信IC可以应用于：工业控制板，电源检测系统，安防设备，门禁系统，楼层烟雾报警系统，电 脑，打印机等。
替换型号 78M05 78M06 78M08 78M09 78M12
公司新推IC及替换型号
一：线性稳压器 序号 型号 1： P78M05 2： P78M06 3： P78M08 4： P78M09 5： P78M12 特点：应用简单，转换效率低，成本低 规格 TO252封装，稳压输出固定+5V TO252封装，稳压输出固定+6V TO252封装，稳压输出固定+8V TO252封装，稳压输出固定+9V TO252封装，稳压输出固定+12V
二：开关式降压IC 序号 型号 规格 1： P2575s-3.3 SOT263封装，固定输出+3.3V 2： P2575T-3.3 TO220封装，固定输出+3.3V 3： P2575S-5.0 SOT263封装，固定输出+5V 4： P2575T-5.0 TO220封装，固定输出+5V 5： P2575S-12 SOT263封装，固定输出+12V 6： P2575T-12 TO220封装，固定输出+12V 7： P2575S-ADJ SOT263封装，输出可调 8： P2575T-ADJ TO220封装，输出可调 9： P2576S-3.3 SOT263封装，固定输出+3.3V 10： P2576T-3.3 TO220封装，固定输出+3.3V 11： P2576S-5.0 SOT263封装，固定输出+5V 12： P2576T-5.O TO220封装，固定输出+5V 13： P2576S-12 SOT263封装，固定输出+12V 14： P2576T-12 TO220封装，固定输出+12V 15： P2576S-ADJ SOT263封装，输出可调 16： P2576T-ADJ TO220封装，输出可调 17： P2596S-3.3 SOT263封装，固定输出+3.3V 18： P2596T-3.3 TO220封装，固定输出+3.3V 19： P2596S-5.0 SOT263封装，固定输出+5V 20： P2596T-5.0 TO220封装，固定输出+5V 21： P2596S-12 SOT263封装，固定输出+12V 22： P2596T-12 TO220封装，固定输出+12V 23： P2596T-ADJ TO220封装，输出可调 24： P2596S-ADJ SOT263封装，输出可调 特点：开关式降压IC，转换效率高，2575输出1A，2576/2596系列最大可输出3A，如2575/2576尾缀带有 HV输入可高达DC60V。默认输入40V。2596与2576两点不同1：开关频率2596为150K，2576为52K。2：259 最大输入为40V。 三：通信IC 序号 型号 1： PFN485CSA 2： PFN485ESA 3： PFN232CSE 4： PFN232ESE
MAX487ESA中文资料
For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .General DescriptionThe MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 are low-power transceivers for RS-485 and RS-422 communication. Each part contains one driver and one receiver. The MAX483, MAX487, MAX488, and MAX489feature reduced slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables,thus allowing error-free data transmission up to 250kbps.The driver slew rates of the MAX481, MAX485, MAX490,MAX491, and MAX1487 are not limited, allowing them to transmit up to 2.5Mbps.These transceivers draw between 120µA and 500µA of supply current when unloaded or fully loaded with disabled drivers. Additionally, the MAX481, MAX483, and MAX487have a low-current shutdown mode in which they consume only 0.1µA. All parts operate from a single 5V supply.Drivers are short-circuit current limited and are protected against excessive power dissipation by thermal shutdown circuitry that places the driver outputs into a high-imped-ance state. The receiver input has a fail-safe feature that guarantees a logic-high output if the input is open circuit.The MAX487 and MAX1487 feature quarter-unit-load receiver input impedance, allowing up to 128 MAX487/MAX1487 transceivers on the bus. Full-duplex communi-cations are obtained using the MAX488–MAX491, while the MAX481, MAX483, MAX485, MAX487, and MAX1487are designed for half-duplex applications.________________________ApplicationsLow-Power RS-485 Transceivers Low-Power RS-422 Transceivers Level TranslatorsTransceivers for EMI-Sensitive Applications Industrial-Control Local Area Networks__Next Generation Device Features♦For Fault-Tolerant ApplicationsMAX3430: ±80V Fault-Protected, Fail-Safe, 1/4Unit Load, +3.3V, RS-485 TransceiverMAX3440E–MAX3444E: ±15kV ESD-Protected,±60V Fault-Protected, 10Mbps, Fail-Safe, RS-485/J1708 Transceivers♦For Space-Constrained ApplicationsMAX3460–MAX3464: +5V, Fail-Safe, 20Mbps,Profibus RS-485/RS-422 TransceiversMAX3362: +3.3V, High-Speed, RS-485/RS-422Transceiver in a SOT23 PackageMAX3280E–MAX3284E: ±15kV ESD-Protected,52Mbps, +3V to +5.5V, SOT23, RS-485/RS-422,True Fail-Safe ReceiversMAX3293/MAX3294/MAX3295: 20Mbps, +3.3V,SOT23, RS-855/RS-422 Transmitters ♦For Multiple Transceiver ApplicationsMAX3030E–MAX3033E: ±15kV ESD-Protected,+3.3V, Quad RS-422 Transmitters ♦For Fail-Safe ApplicationsMAX3080–MAX3089: Fail-Safe, High-Speed (10Mbps), Slew-Rate-Limited RS-485/RS-422Transceivers♦For Low-Voltage ApplicationsMAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E: +3.3V Powered, ±15kV ESD-Protected, 12Mbps, Slew-Rate-Limited,True RS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers______________________________________________________________Selection Table19-0122; Rev 8; 10/03Ordering Information appears at end of data sheet.M A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGSSupply Voltage (V CC ).............................................................12V Control Input Voltage (RE , DE)...................-0.5V to (V CC + 0.5V)Driver Input Voltage (DI).............................-0.5V to (V CC + 0.5V)Driver Output Voltage (A, B)...................................-8V to +12.5V Receiver Input Voltage (A, B).................................-8V to +12.5V Receiver Output Voltage (RO).....................-0.5V to (V CC +0.5V)Continuous Power Dissipation (T A = +70°C)8-Pin Plastic DIP (derate 9.09mW/°C above +70°C)....727mW 14-Pin Plastic DIP (derate 10.00mW/°C above +70°C)..800mW 8-Pin SO (derate 5.88mW/°C above +70°C).................471mW14-Pin SO (derate 8.33mW/°C above +70°C)...............667mW 8-Pin µMAX (derate 4.1mW/°C above +70°C)..............830mW 8-Pin CERDIP (derate 8.00mW/°C above +70°C).........640mW 14-Pin CERDIP (derate 9.09mW/°C above +70°C).......727mW Operating Temperature RangesMAX4_ _C_ _/MAX1487C_ A...............................0°C to +70°C MAX4__E_ _/MAX1487E_ A.............................-40°C to +85°C MAX4__MJ_/MAX1487MJA...........................-55°C to +125°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering, 10sec).............................+300°CDC ELECTRICAL CHARACTERISTICS(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)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.V V IN = -7VV IN = 12V V IN = -7V V IN = 12V Input Current (A, B)I IN2V TH k Ω48-7V ≤V CM ≤12V, MAX487/MAX1487R INReceiver Input Resistance -7V ≤V CM ≤12V, all devices except MAX487/MAX1487R = 27Ω(RS-485), Figure 40.4V ≤V O ≤2.4VR = 50Ω(RS-422)I O = 4mA, V ID = -200mV I O = -4mA, V ID = 200mV V CM = 0V-7V ≤V CM ≤12V DE, DI, RE DE, DI, RE MAX487/MAX1487,DE = 0V, V CC = 0V or 5.25VDE, DI, RE R = 27Ωor 50Ω, Figure 4R = 27Ωor 50Ω, Figure 4R = 27Ωor 50Ω, Figure 4DE = 0V;V CC = 0V or 5.25V,all devices except MAX487/MAX1487CONDITIONSk Ω12µA ±1I OZRThree-State (high impedance)Output Current at ReceiverV 0.4V OL Receiver Output Low Voltage 3.5V OH Receiver Output High Voltage mV 70∆V TH Receiver Input Hysteresis V -0.20.2Receiver Differential Threshold Voltage-0.2mA 0.25mA-0.81.01.55V OD2Differential Driver Output (with load)V 2V 5V OD1Differential Driver Output (no load)µA±2I IN1Input CurrentV 0.8V IL Input Low Voltage V 2.0V IH Input High Voltage V 0.2∆V OD Change in Magnitude of Driver Common-Mode Output Voltage for Complementary Output States V 0.2∆V OD Change in Magnitude of Driver Differential Output Voltage for Complementary Output States V 3V OC Driver Common-Mode Output VoltageUNITS MINTYPMAX SYMBOL PARAMETERMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers_______________________________________________________________________________________3SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)DC ELECTRICAL CHARACTERISTICS (continued)(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)ns 103060t PHLDriver Rise or Fall Time Figures 6 and 8, R DIFF = 54Ω, C L1= C L2= 100pF ns MAX490M, MAX491M MAX490C/E, MAX491C/E2090150MAX481, MAX485, MAX1487MAX490M, MAX491MMAX490C/E, MAX491C/E MAX481, MAX485, MAX1487Figures 6 and 8, R DIFF = 54Ω,C L1= C L2= 100pF MAX481 (Note 5)Figures 5 and 11, C RL = 15pF, S2 closedFigures 5 and 11, C RL = 15pF, S1 closed Figures 5 and 11, C RL = 15pF, S2 closed Figures 5 and 11, C RL = 15pF, S1 closed Figures 6 and 10, R DIFF = 54Ω,C L1= C L2= 100pFFigures 6 and 8,R DIFF = 54Ω,C L1= C L2= 100pF Figures 6 and 10,R DIFF = 54Ω,C L1= C L2= 100pF CONDITIONS ns 510t SKEW ns50200600t SHDNTime to ShutdownMbps 2.5f MAX Maximum Data Rate ns 2050t HZ Receiver Disable Time from High ns 103060t PLH 2050t LZ Receiver Disable Time from Low ns 2050t ZH Driver Input to Output Receiver Enable to Output High ns 2050t ZL Receiver Enable to Output Low 2090200ns ns 134070t HZ t SKD Driver Disable Time from High |t PLH - t PHL |DifferentialReceiver Skewns 4070t LZ Driver Disable Time from Low ns 4070t ZL Driver Enable to Output Low 31540ns51525ns 31540t R , t F 2090200Driver Output Skew to Output t PLH , t PHL Receiver Input to Output4070t ZH Driver Enable to Output High UNITS MIN TYP MAX SYMBOL PARAMETERFigures 7 and 9, C L = 100pF, S2 closed Figures 7 and 9, C L = 100pF, S1 closed Figures 7 and 9, C L = 15pF, S1 closed Figures 7 and 9, C L = 15pF, S2 closedM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 4_______________________________________________________________________________________SWITCHING CHARACTERISTICS—MAX483, MAX487/MAX488/MAX489(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487 (continued)(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)3001000Figures 7 and 9, C L = 100pF, S2 closed Figures 7 and 9, C L = 100pF, S1 closed Figures 5 and 11, C L = 15pF, S2 closed,A - B = 2VCONDITIONSns 40100t ZH(SHDN)Driver Enable from Shutdown toOutput High (MAX481)nsFigures 5 and 11, C L = 15pF, S1 closed,B - A = 2Vt ZL(SHDN)Receiver Enable from Shutdownto Output Low (MAX481)ns 40100t ZL(SHDN)Driver Enable from Shutdown toOutput Low (MAX481)ns 3001000t ZH(SHDN)Receiver Enable from Shutdownto Output High (MAX481)UNITS MINTYP MAX SYMBOLPARAMETERt PLH t SKEW Figures 6 and 8, R DIFF = 54Ω,C L1= C L2= 100pFt PHL Figures 6 and 8, R DIFF = 54Ω,C L1= C L2= 100pFDriver Input to Output Driver Output Skew to Output ns 100800ns ns 2000MAX483/MAX487, Figures 7 and 9,C L = 100pF, S2 closedt ZH(SHDN)Driver Enable from Shutdown to Output High2502000ns2500MAX483/MAX487, Figures 5 and 11,C L = 15pF, S1 closedt ZL(SHDN)Receiver Enable from Shutdown to Output Lowns 2500MAX483/MAX487, Figures 5 and 11,C L = 15pF, S2 closedt ZH(SHDN)Receiver Enable from Shutdown to Output Highns 2000MAX483/MAX487, Figures 7 and 9,C L = 100pF, S1 closedt ZL(SHDN)Driver Enable from Shutdown to Output Lowns 50200600MAX483/MAX487 (Note 5) t SHDN Time to Shutdownt PHL t PLH , t PHL < 50% of data period Figures 5 and 11, C RL = 15pF, S2 closed Figures 5 and 11, C RL = 15pF, S1 closed Figures 5 and 11, C RL = 15pF, S2 closed Figures 5 and 11, C RL = 15pF, S1 closed Figures 7 and 9, C L = 15pF, S2 closed Figures 6 and 10, R DIFF = 54Ω,C L1= C L2= 100pFFigures 7 and 9, C L = 15pF, S1 closed Figures 7 and 9, C L = 100pF, S1 closed Figures 7 and 9, C L = 100pF, S2 closed CONDITIONSkbps 250f MAX 2508002000Maximum Data Rate ns 2050t HZ Receiver Disable Time from High ns 25080020002050t LZ Receiver Disable Time from Low ns 2050t ZH Receiver Enable to Output High ns 2050t ZL Receiver Enable to Output Low ns ns 1003003000t HZ t SKD Driver Disable Time from High I t PLH - t PHL I DifferentialReceiver SkewFigures 6 and 10, R DIFF = 54Ω,C L1= C L2= 100pFns 3003000t LZ Driver Disable Time from Low ns 2502000t ZL Driver Enable to Output Low ns Figures 6 and 8, R DIFF = 54Ω,C L1= C L2= 100pFns 2502000t R , t F 2502000Driver Rise or Fall Time ns t PLH Receiver Input to Output2502000t ZH Driver Enable to Output High UNITS MIN TYP MAX SYMBOL PARAMETERMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers_______________________________________________________________________________________530002.5OUTPUT CURRENT vs.RECEIVER OUTPUT LOW VOLTAGE525M A X 481-01OUTPUT LOW VOLTAGE (V)O U T P U T C U R R E N T (m A )1.515100.51.02.0203540450.90.1-50-252575RECEIVER OUTPUT LOW VOLTAGE vs.TEMPERATURE0.30.7TEMPERATURE (°C)O U T P U TL O W V O L T A G E (V )500.50.80.20.60.40100125-20-41.5 2.0 3.0 5.0OUTPUT CURRENT vs.RECEIVER OUTPUT HIGH VOLTAGE-8-16M A X 481-02OUTPUT HIGH VOLTAGE (V)O U T P U T C U R R E N T (m A )2.5 4.0-12-18-6-14-10-203.54.5 4.83.2-50-252575RECEIVER OUTPUT HIGH VOLTAGE vs.TEMPERATURE3.64.4TEMPERATURE (°C)O U T P UT H I G H V O L T A G E (V )0504.04.63.44.23.83.01001259000 1.0 3.0 4.5DRIVER OUTPUT CURRENT vs.DIFFERENTIAL OUTPUT VOLTAGE1070M A X 481-05DIFFERENTIAL OUTPUT VOLTAGE (V)O U T P U T C U R R E N T (m A )2.0 4.05030806040200.5 1.5 2.53.5 2.31.5-50-2525125DRIVER DIFFERENTIAL OUTPUT VOLTAGEvs. TEMPERATURE1.72.1TEMPERATURE (°C)D I F FE R E N T I A L O U T P U T V O L T A G E (V )751.92.21.62.01.8100502.4__________________________________________Typical Operating Characteristics(V CC = 5V, T A = +25°C, unless otherwise noted.)NOTES FOR ELECTRICAL/SWITCHING CHARACTERISTICSNote 1:All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to deviceground unless otherwise specified.Note 2:All typical specifications are given for V CC = 5V and T A = +25°C.Note 3:Supply current specification is valid for loaded transmitters when DE = 0V.Note 4:Applies to peak current. See Typical Operating Characteristics.Note 5:The MAX481/MAX483/MAX487 are put into shutdown by bringing RE high and DE low. If the inputs are in this state for lessthan 50ns, the parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 600ns, the parts are guaranteed to have entered shutdown. See Low-Power Shutdown Mode section.M A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 6___________________________________________________________________________________________________________________Typical Operating Characteristics (continued)(V CC = 5V, T A = +25°C, unless otherwise noted.)120008OUTPUT CURRENT vs.DRIVER OUTPUT LOW VOLTAGE20100M A X 481-07OUTPUT LOW VOLTAGE (V)O U T P U T C U R R E N T (m A )6604024801012140-1200-7-5-15OUTPUT CURRENT vs.DRIVER OUTPUT HIGH VOLTAGE-20-80M A X 481-08OUTPUT HIGH VOLTAGE (V)O U T P U T C U R R E N T (m A )-31-603-6-4-2024-100-40100-40-60-2040100120MAX1487SUPPLY CURRENT vs. TEMPERATURE300TEMPERATURE (°C)S U P P L Y C U R R E N T (µA )20608050020060040000140100-50-2550100MAX481/MAX485/MAX490/MAX491SUPPLY CURRENT vs. TEMPERATURE300TEMPERATURE (°C)S U P P L Y C U R R E N T (µA )257550020060040000125100-50-2550100MAX483/MAX487–MAX489SUPPLY CURRENT vs. TEMPERATURE300TEMPERATURE (°C)S U P P L Y C U R R E N T (µA )257550020060040000125MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers_______________________________________________________________________________________7______________________________________________________________Pin DescriptionFigure 1. MAX481/MAX483/MAX485/MAX487/MAX1487 Pin Configuration and Typical Operating CircuitM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487__________Applications InformationThe MAX481/MAX483/MAX485/MAX487–MAX491 and MAX1487 are low-power transceivers for RS-485 and RS-422 communications. The MAX481, MAX485, MAX490,MAX491, and MAX1487 can transmit and receive at data rates up to 2.5Mbps, while the MAX483, MAX487,MAX488, and MAX489 are specified for data rates up to 250kbps. The MAX488–MAX491 are full-duplex trans-ceivers while the MAX481, MAX483, MAX485, MAX487,and MAX1487 are half-duplex. In addition, Driver Enable (DE) and Receiver Enable (RE) pins are included on the MAX481, MAX483, MAX485, MAX487, MAX489,MAX491, and MAX1487. When disabled, the driver and receiver outputs are high impedance.MAX487/MAX1487:128 Transceivers on the BusThe 48k Ω, 1/4-unit-load receiver input impedance of the MAX487 and MAX1487 allows up to 128 transceivers on a bus, compared to the 1-unit load (12k Ωinput impedance) of standard RS-485 drivers (32 trans-ceivers maximum). Any combination of MAX487/MAX1487 and other RS-485 transceivers with a total of 32 unit loads or less can be put on the bus. The MAX481/MAX483/MAX485 and MAX488–MAX491 have standard 12k ΩReceiver Input impedance.Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 8_______________________________________________________________________________________Figure 2. MAX488/MAX490 Pin Configuration and Typical Operating CircuitFigure 3. MAX489/MAX491 Pin Configuration and Typical Operating CircuitMAX483/MAX487/MAX488/MAX489:Reduced EMI and ReflectionsThe MAX483 and MAX487–MAX489 are slew-rate limit-ed, minimizing EMI and reducing reflections caused by improperly terminated cables. Figure 12 shows the dri-ver output waveform and its Fourier analysis of a 150kHz signal transmitted by a MAX481, MAX485,MAX490, MAX491, or MAX1487. High-frequency har-monics with large amplitudes are evident. Figure 13shows the same information displayed for a MAX483,MAX487, MAX488, or MAX489 transmitting under the same conditions. Figure 13’s high-frequency harmonics have much lower amplitudes, and the potential for EMI is significantly reduced.MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers_______________________________________________________________________________________9_________________________________________________________________Test CircuitsFigure 4. Driver DC Test Load Figure 5. Receiver Timing Test LoadFigure 6. Driver/Receiver Timing Test Circuit Figure 7. Driver Timing Test LoadM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 10_______________________________________________________Switching Waveforms_________________Function Tables (MAX481/MAX483/MAX485/MAX487/MAX1487)Figure 8. Driver Propagation DelaysFigure 9. Driver Enable and Disable Times (except MAX488 and MAX490)Figure 10. Receiver Propagation DelaysFigure 11. Receiver Enable and Disable Times (except MAX488and MAX490)Table 1. TransmittingTable 2. ReceivingLow-Power Shutdown Mode (MAX481/MAX483/MAX487)A low-power shutdown mode is initiated by bringing both RE high and DE low. The devices will not shut down unless both the driver and receiver are disabled.In shutdown, the devices typically draw only 0.1µA of supply current.RE and DE may be driven simultaneously; the parts are guaranteed not to enter shutdown if RE is high and DE is low for less than 50ns. If the inputs are in this state for at least 600ns, the parts are guaranteed to enter shutdown.For the MAX481, MAX483, and MAX487, the t ZH and t ZL enable times assume the part was not in the low-power shutdown state (the MAX485/MAX488–MAX491and MAX1487 can not be shut down). The t ZH(SHDN)and t ZL(SHDN)enable times assume the parts were shut down (see Electrical Characteristics ).It takes the drivers and receivers longer to become enabled from the low-power shutdown state (t ZH(SHDN ), t ZL(SHDN)) than from the operating mode (t ZH , t ZL ). (The parts are in operating mode if the –R —E –,DE inputs equal a logical 0,1 or 1,1 or 0, 0.)Driver Output ProtectionExcessive output current and power dissipation caused by faults or by bus contention are prevented by two mechanisms. A foldback current limit on the output stage provides immediate protection against short cir-cuits over the whole common-mode voltage range (see Typical Operating Characteristics ). In addition, a ther-mal shutdown circuit forces the driver outputs into a high-impedance state if the die temperature rises excessively.Propagation DelayMany digital encoding schemes depend on the differ-ence between the driver and receiver propagation delay times. Typical propagation delays are shown in Figures 15–18 using Figure 14’s test circuit.The difference in receiver delay times, | t PLH - t PHL |, is typically under 13ns for the MAX481, MAX485,MAX490, MAX491, and MAX1487 and is typically less than 100ns for the MAX483 and MAX487–MAX489.The driver skew times are typically 5ns (10ns max) for the MAX481, MAX485, MAX490, MAX491, and MAX1487, and are typically 100ns (800ns max) for the MAX483 and MAX487–MAX489.MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers______________________________________________________________________________________1110dB/div0Hz5MHz500kHz/div10dB/div0Hz5MHz500kHz/divFigure 12. Driver Output Waveform and FFT Plot of MAX481/MAX485/MAX490/MAX491/MAX1487 Transmitting a 150kHz SignalFigure 13. Driver Output Waveform and FFT Plot of MAX483/MAX487–MAX489 Transmitting a 150kHz SignalM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 12______________________________________________________________________________________V CC = 5V T A = +25°CV CC = 5V T A = +25°CV CC = 5V T A = +25°CV CC = 5V T A = +25°CFigure 14. Receiver Propagation Delay Test CircuitFigure 15. MAX481/MAX485/MAX490/MAX491/MAX1487Receiver t PHLFigure 16. MAX481/MAX485/MAX490/MAX491/MAX1487Receiver t PLHPHL Figure 18. MAX483, MAX487–MAX489 Receiver t PLHLine Length vs. Data RateThe RS-485/RS-422 standard covers line lengths up to 4000 feet. For line lengths greater than 4000 feet, see Figure 23.Figures 19 and 20 show the system differential voltage for the parts driving 4000 feet of 26AWG twisted-pair wire at 110kHz into 120Ωloads.Typical ApplicationsThe MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 transceivers are designed for bidirectional data communications on multipoint bus transmission lines.Figures 21 and 22 show typical network applications circuits. These parts can also be used as line repeaters, with cable lengths longer than 4000 feet, as shown in Figure 23.To minimize reflections, the line should be terminated at both ends in its characteristic impedance, and stub lengths off the main line should be kept as short as possi-ble. The slew-rate-limited MAX483 and MAX487–MAX489are more tolerant of imperfect termination.MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers______________________________________________________________________________________13DIV Y -V ZRO5V 0V1V0V -1V5V 0V2µs/divFigure 19. MAX481/MAX485/MAX490/MAX491/MAX1487 System Differential Voltage at 110kHz Driving 4000ft of Cable Figure 20. MAX483, MAX487–MAX489 System Differential Voltage at 110kHz Driving 4000ft of CableFigure 21. MAX481/MAX483/MAX485/MAX487/MAX1487 Typical Half-Duplex RS-485 NetworkM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 14______________________________________________________________________________________Figure 22. MAX488–MAX491 Full-Duplex RS-485 NetworkFigure 23. Line Repeater for MAX488–MAX491Isolated RS-485For isolated RS-485 applications, see the MAX253 and MAX1480 data sheets.MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers______________________________________________________________________________________15_______________Ordering Information_________________Chip TopographiesMAX481/MAX483/MAX485/MAX487/MAX1487N.C. RO 0.054"(1.372mm)0.080"(2.032mm)DE DIGND B N.C.V CCARE * Contact factory for dice specifications.__Ordering Information (continued)M A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 16______________________________________________________________________________________TRANSISTOR COUNT: 248SUBSTRATE CONNECTED TO GNDMAX488/MAX490B RO 0.054"(1.372mm)0.080"(2.032mm)N.C. DIGND Z A V CCYN.C._____________________________________________Chip Topographies (continued)MAX489/MAX491B RO 0.054"(1.372mm)0.080"(2.032mm)DE DIGND Z A V CCYREMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers______________________________________________________________________________________17Package Information(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to /packages .)S O I C N .E P SM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 18______________________________________________________________________________________Package Information (continued)(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to /packages .)MAX481/MAX483/MAX485/MAX487–MAX491Low-Power, Slew-Rate-Limited RS-485/RS-422 TransceiversMaxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________19©2003 Maxim Integrated ProductsPrinted USAis a registered trademark of Maxim Integrated Products.M A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487P D I P N .E PSPackage Information (continued)(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to /packages .)。
驱动器正确选型的方法
驱动器正确选型的方法（驱动器型号的确定方法）选择驱动器时需满足以下四点相匹配。
1.电机类型普通直流有刷电机引线特征：两根电源线或两根电源线与一测速线；两电源线多数为红黑两色；电源正负极交换后电机将反转。
直流有刷伺服电机引线特征：两根电源线与4根或5根编码器信号线。
直流无感无刷电机引线特征：三根电源线，多数为黄绿蓝三色。
直流有感无刷电机引线特征：三根电源线与5根霍尔信号线，电源线通常较信号线粗，电源线多数为黄绿蓝三色，霍尔线多数为红黄绿蓝黑五色。
直流无刷伺服电机引线特征：三根电源线与4根或5根编码器信号线。
爱控电机驱动器中AQMH2403ND、AQMH2407ND、AQMH3615NS、AQMD2410NS、AQMD3610NS、AQMD3620NS、AQMD3630NS、AQMD6030NS支持的电机类型为普通直流有刷电机；AQMD3605BLS、AQMD3608BLS、AQMD6010BLS、AQMD6020BLS支持的电机类型为直流有感无刷电机。
2.电机额定电压额定电压是电器长时间工作时所适用的最佳电压。
电机额定电压通常在电机铭牌或数据手册上可找到。
常见的电机额定电压有6V、12V、24V、36V、48V、60V、110V、220V、380V等。
AQMH2403ND电压范围6.8V-27V，无过压或欠压保护，电压过高或过低都可能损坏驱动器。
AQMD2410NS电压范围8V-27V，无过压保护，电压过高可能损坏驱动器。
欠压时不能正常工作。
AQMD3610NS电压范围7V-41V，无过压保护，电压过高可能损坏驱动器。
欠压时不能正常工作。
AQMD3605BLS、AQMD63608BLS、AQMH3615NS、AQMD3620NS、AQMD3630NS 电压范围6.5V-40V，有欠压保护，电压过低不工作；无过压保护，电压过高可能损坏驱动器。
AQMD6030NS、AQMD6010BLS、AQMD6020BLS电压范围8.5V-66V，有欠压保护，电压过低不工作；无过压保护，电压过高可能损坏驱动器。
热泵干燥控制系统的设计
热泵干燥控制系统的设计尚巧赠;王勇;梁月肖【摘要】T his paper introduces the composition of heat pump drying system and the realiza‐tion of control system .T he automatic detection and control technology is applied to the heat pump drying process .The heat pump drying control system collects working parameters of the drying process in real time ,and controls actuators according to the setted process parame‐ters ,which enables the heat pump drying system to achieve the most optimal working state .%主要介绍了热泵干燥系统的构成以及控制系统的实现，将自动检测控制技术运用到热泵干燥过程中。
热泵干燥控制系统实时采集干燥过程中的工况参数，按照设定好的工艺参数，控制执行机构，使热泵干燥系统达到最优工作状态。
【期刊名称】《河北省科学院学报》【年(卷),期】2014(000)004【总页数】4页(P32-35)【关键词】热泵干燥;控制系统;传感器【作者】尚巧赠;王勇;梁月肖【作者单位】河北省机电一体化中试基地，河北石家庄 050081;河北省机电一体化中试基地，河北石家庄 050081;石家庄科技信息职业学院，河北石家庄 050081【正文语种】中文【中图分类】S226.6热泵干燥技术越来越成熟，应用的行业越来越多，该技术从某种程度上，缓解了能源压力。
把自动控制运用于热泵干燥系统中，使之能够根据物料干燥的逻辑自动控制，是热泵干燥发展的必然趋势。
max485芯片使用说明
MAX485:
用于RS-485与RS-422通信的低功耗收发器接入总线数：32
引脚数：8
静态电流：120uA
电源电压(V
CC
) .5V
引脚描述：PIN 符号功能
1 RO 接收器输出端
如果输入端电压A-B> 200mV，输出端RO输出高电平；如果输入端电压B-A > 200mV，输出端RO输出低电平；
2 RE 接收器输出使能端。
当RE为低电平时，接收器工作；
当RE为高电平时，接收器输出端为高阻态。
3 DE 驱动器输出使能端。
当DE为高电平时，驱动器工作；
当DE为低电平时，驱动器关断，输出端A和B为高阻态。
当驱动器工作时，本器件相当于一个线性驱动器。
但它为高阻态的时候，如果RE为低，器件的功能相当于一个线性接收器。
4 DI 驱动器输入端。
DI为低电平时，输出A为低、B为高。
DI为高电平时，输出A为高、B为低。
5 GND 地
6 A 接收器同相输入端和驱动器同相输出端
7 B 接收器反相输入端和驱动器反相输出端
8 V
CC 电源电压（4.75V ≤V CC≤5.25V）。
启珑微电子产品手册说明书
产品手册PRODUCT MANUAL(北京︶有限公司并一直致力于为工业智能控制、医疗设备、轨道交通、智能交通以及智能家居等领域提供更优质的产品与服务。
公司具有深厚的文化底蕴，由多位有欧美留学、工作经历的归国人员创办，坚实的理论功底和丰富的芯片设计经验奠定了启珑微电子的高起点和高水准，并迅速成长为业内具有自主知识产权的中国IC设计品牌之一。
产品手册01序号产品型号封装形式产品概述兼容型号1CLM811HST-AXC TQFP-48SL811HST-AXC 2CLCP82C55AZ DIP-40CP82C55AZ 3CLIP82C55AZ DIP-40IP82C55AZ 4CLCS82C55AZ PLCC-44CS82C55AZ 5CLIS82C55AZ PLCC-44IS82C55AZ 6CLCQ82C55AZ MQFP-44CQ82C55AZ 7CLIQ82C55AZ MQFP-44IQ82C55AZ 8CLID82C55AZ DIP-40ID82C55A 9CLMD82C55A/B DIP-40MD82C55A/B 10CLMD82C55QA DIP-40MD82C55QA 11CLM65HVD230D SOIC-8SN65HVD230D 12CLM65HVD230QD SOIC-8SN65HVD230QD 13CLM65HVD231D SOIC-8SN65HVD231D 14CLM65HVD231QD SOIC-8SN65HVD231QD 15CLM65HVD232D SOIC-8SN65HVD232D 16CLM65HVD232QD SOIC-8SN65HVD232QD 17CLM65HVD233D SOIC-8具有待机模式和环回功能的 3.3V SN65HVD233D 18CLM65HVD233HD SOIC-8具有待机模式和环回功能的 3.3V SN65HVD233HD 19CLM65HVD233QDRQ1SOIC-8具有待机模式和环回功能的 3.3V SN65HVD233QDRQ120CLM65HVD233MDREP SOIC-8具有待机模式和环回功能的 3.3V SN65HVD233MDREP产品手册02序号产品型号封装形式产品概述兼容型号21CLM65HVD234D SOIC-8SN65HVD234D 22CLM65HVD234QDRQ1SOIC-8SN65HVD234QDRQ123CLM65HVD235D SOIC-8SN65HVD235D 24CLM65HVD235QDRQ1SOIC-8SN65HVD235QDRQ125CLM75176BPS SOIC-8SN75176BPSR 26CLM75176BDR SOIC-8SN75176BDR 27CLM75176ADR SOIC-8SN75176ADR 28CLM75176AP DIP-8SN75176AP 29CLM76176BP DIP-8SN75176BP 30CLM75179BPS SOIC-8SN75179BPS 31CLM75179BDR SOIC-8SN75179BDR 32CLM75179AP DIP-8SN75179AP 33CLM75179BP DIP-8SN75179BP 34CLM65HVD08D SOIC-8SN65HVD08D 35CLM65HVD08P DIP-8SN65HVD08P 36CLM65HVD75D SOIC-8具有IEC ESD保护功能和20Mbps的SN65HVD75D 37CLM65HVD75DGK VSSOIC-8具有IEC ESD保护功能和20Mbps的SN65HVD75DGK 38CLM65HVD75DRBT VDFN-8具有IEC ESD保护功能和20Mbps的SN65HVD75DRBT 39CLM3085CPA+DIP-8(10Mbps)、限摆率RS-485/MAX3085CPA+40CLM3085EPA+DIP-8(10Mbps)、限摆率RS-485/MAX3085EPA+产品手册03序号产品型号封装形式产品概述兼容型号41CLM3085EEPA DIP-8(10Mbps)、限摆率RS-485/MAX3085EEPA 42CLM3085CSA+T SOIC-8(10Mbps)、限摆率RS-485/MAX3085CSA+43CLM3085ECSA+T MSOIC-8(10Mbps)、限摆率RS-485/MAX3085ECSA+T 44CLM3085ESA+T SOIC-8(10Mbps)、限摆率RS-485/MAX3085ESA+45CLM3085EESA+T SOIC-8(10Mbps)、限摆率RS-485/MAX3085EESA+46CLM3088CSA+T SOIC-8MAX3088CSA+T 47CLM3088ECSA+T SOIC-8MAX3088ECSA+T 48CLM3088ESA+T SOIC-8MAX3088ESA+T 49CLM3088EESA+T SOIC-8MAX3088EESA+T 50CLM3088CPA+DIP-8MAX3088CPA+51CLM3088ECPA+DIP-8MAX3088ECPA+52CLM3088EPA+DIP-8MAX3088EPA+53CLM3088EEPA+DIP-8MAX3088EEPA+54CLM485CPA+DIP-8低功耗、限摆率、RS-485/RS-422MAX485CPA+55CLM485ECPA+DIP-8低功耗、限摆率、RS-485/RS-422MAX485ECPA+56CLM485EPA+DIP-8低功耗、限摆率、RS-485/RS-422MAX485EPA+57CLM485EEPA+DIP-8低功耗、限摆率、RS-485/RS-422MAX485EEPA+58CLM485CSA+SOIC-8低功耗、限摆率、RS-485/RS-422MAX485CSA+59CLM485ESA+SOIC-8低功耗、限摆率、RS-485/RS-422MAX485ESA+60CLM485EESA+SOIC-8低功耗、限摆率、RS-485/RS-422MAX485EESA+产品手册04序号产品型号封装形式产品概述兼容型号61CLM3490CSA+SOIC-8 3.3V供电、10Mbps、限摆率、真MAX3490CSA+62CLM3490ECSA+SOIC-8 3.3V供电、10Mbps、限摆率、真MAX3490ESA+63CLM3490ESA+SOIC-8 3.3V供电、10Mbps、限摆率、真MAX3490ESA+64CLM3490EESA+SOIC-8 3.3V供电、10Mbps、限摆率、真MAX3490EESA+65CLM3491CSD SOP-14 3.3V供电、10Mbps、限摆率、真MAX3491CSD+66CLM3491ECSD+SOP-14 3.3V供电、10Mbps、限摆率、真MAX3491ECSD+67CLM3491ESD+SOP-14 3.3V供电、10Mbps、限摆率、真MAX3491ESD+68CLM3491EESD+SOP-14 3.3V供电、10Mbps、限摆率、真MAX3491EESD+69CLM490CSA+SOIC-8低功耗、限摆率、RS-485/RS-422MAX490CSA+70CLM490ECSA+SOIC-8低功耗、限摆率、RS-485/RS-422MAX490ECSA+71CLM490ESA+SOIC-8低功耗、限摆率、RS-485/RS-422MAX490ESA+72CLM490EESA+SOIC-8低功耗、限摆率、RS-485/RS-422MAX490EESA+73CLM490CPA+DIP-8低功耗、限摆率、RS-485/RS-422MAX490CPA+74CLM490ECPA+DIP-8低功耗、限摆率、RS-485/RS-422MAX490ECPA+75CLM490EPA+DIP-8低功耗、限摆率、RS-485/RS-422MAX490EPA+76CLM490EEPA+DIP-8低功耗、限摆率、RS-485/RS-422MAX490EEPA+77CLM488CSA+SOIC-8低功耗、限摆率、RS-485/RS-422MAX488CSA+78CLM488ECSA+SOIC-8低功耗、限摆率、RS-485/RS-422MAX488ECSA+79CLM488ESA+SOIC-8低功耗、限摆率、RS-485/RS-422MAX488ESA+80CLM488EESA+SOIC-8低功耗、限摆率、RS-485/RS-422MAX488EESA+产品手册序号产品型号封装形式产品概述兼容型号81CLM488CPA+DIP-8MAX488CPA+82CLM488ECPA+DIP-8MAX488ECPA+83CLM488EPA+DIP-8MAX488EPA+84CLM488EEPA+DIP-8MAX488EEPA+85CLM232CSE SOIC-16MAX232CSE+T86CLM232ECSE SOIC-16MAX232ECSE+87CLM232ESE SOIC-16MAX232ESE+T88CLM232EESE SOIC-16MAX232EESE+T89CLM232CPE DIP-16MAX232CPE+90CLM232ECPE DIP-16MAX232ECPE+91CLM232EPE DIP-16MAX232EPE+92CLM232EEPE DIP-16MAX232EEPE+93CLM232CWE SOIC-16MAX232CWE+T94CLM232ECWE SOIC-16MAX232ECWE+T95CLM232EWE SOIC-16MAX232EWE+T96CLM232EEWE SOIC-16MAX232EEWE+T97CLM232ACWE SOIC-16MAX232ACWE+T98CLM232AEWE SOIC-16MAX232AEWE+99CLM3232CSE SOIC-16MAX3232CSE+T 100CLM3232ECSE SOIC-16MAX3232ECSE+T05产品手册06序号产品型号封装形式产品概述兼容型号101CLM3232ESE SOIC-16MAX3232ESE+T 102CLM3232EESE SOIC-16MAX3232EESE+T 103CLM1302S SOIC-8DS1302S+T&R 104CLM1302SN+SOIC-8DS1302SN+T&R 105CLM1302Z+T SOIC-8DS1302Z+T&R 106CLM1302ZN+SOIC-8DS1302ZN+T&R 107CLM1302+DIP-8DS1302+108CLM1302N+DIP-8DS1302N+109CLM307Z+SOIC-8DS1307Z+T&R 110CLM1307ZN+SOIC-8DS1307ZN+T&R 111CLM1307+DIP-8DS1307+112CLM1307N+DIP-8DS1307N+113CLM4717EUB+MSOP-10拟开关MAX4717EUB+114CLM231N/NOPB DIP-8LM231N/NOPB 115CLM231AN/NOPB DIP-8LM231AN/NOPB 116CLM331N/NOPB DIP-8LM331N/NOPB 117CLM331AN/NOPB DIP-8LM331AN/NOPB 118CLM298N Multiwatt-15L298N 119CLM298P POWERSO-20L298P 120CLM2543CDW SOIC-20TLC2543CDW产品手册07序号产品型号封装形式产品概述兼容型号121CLM2543IDW SOIC-20TLC2543IDW 122CLM2543CDB SSOP-20TLC2543CDB 123CLM2543IDB SSOP-20TLC2543IDB 124CLM2543CN DIP-20TLC2543CN 125CLM2543IN DIP-20TLC2543IN 126CLM1543CDW SOIC-20TLC1543CDW 127CLM1543IDW SOIC-20TLC1543IDW 128CLM1543CN DIP-20TLC1543CN 129CLM1543IN DIP-20TLC1543IN 130CLM5615CDGK VSSOIC-8趋稳时间为12.5us并具备上电复位功能的10位、单通道、低功耗DAC TLC5615CDGK 131CLM5615IDGK VSSOIC-8趋稳时间为12.5us并具备上电复位功能的10位、单通道、低功耗DAC TLC5615IGGK 132CLM5615CD SOIC-8趋稳时间为12.5us并具备上电复位功能的10位、单通道、低功耗DAC TLC5615CD 133CLM5615ID SOIC-8趋稳时间为12.5us并具备上电复位功能的10位、单通道、低功耗DAC TLC5615ID 134CLM5615CP DIP-8趋稳时间为12.5us并具备上电复位功能的10位、单通道、低功耗DAC TLC5615CP 135CLM5615IP DIP-8趋稳时间为12.5us并具备上电复位功能的10位、单通道、低功耗DAC TLC5615IP 136CLM3616-00SOP-14IW3616-00137CLM3616-01SOP-14IW3616-01138CLM3617-00SOP-14IW3617-00139CLM3617-01SOP-14IW3617-01140CLM3630-00SOP-14IW3630-00产品手册序号产品型号封装形式产品概述兼容型号141CLM1100-0001BGA-128ASIC从站控制ET1100-0001142CLM1100-0002BGA-128ASIC从站控制ET1100-0002143CLM1100-0003BGA-128ASIC从站控制ET1100-0003144CLM1200-0001QFN-48ASIC从站控制ET1200-0001145CLM1200-0002QFN-48ASIC从站控制ET1200-0002146CLM1200-0003QFN-48ASIC从站控制ET1200-0003147CLM8656ARZ SOIC-8AD8656ARZ148CLM8656ARMZ MSOIC-8AD8656ARMZ149CLM1040T/CM,118SOIC-8TJA1040T/CM,118 150CLM1042T/CM,118SOIC-8TJA1042T/CM,118 151CLM1050T/CM,118SOIC-8TJA1050T/CM,118 152CLM1051T/CM,118SOIC-8TJA1051T/CM,118 153CLM82C250T/YM SOIC-8PCA82C250T/YM 154CLM82C251T/YM SOIC-8PCA82C251T/YM 155CLMEE80C196KC20PLCC-68EE80C196KC20 156CLMEN80C196KC20PLCC-68EN80C196KC20 157CLMN80C196KC20PLCC-68N80C196KC20 158CLMTN80C196KC20PLCC-68TN80C196KC20 159CLMEE87C196KC20PLCC-68EE87C196KC20 160CLMEN87C196KC20PLCC-68EN87C196KC2008产品手册09序号产品型号封装形式产品概述兼容型号161CLMN87C196KC20PLCC-68N87C196KC20162CLMTN87C196KC20PLCC-68TN87C196KC20163CLM8051F020-GQ TQFP-100C8051F020-GQ 164CLM8051F021-GQ TQFP-64C8051F021-GQ 165CLM8051F330-GM VFQFN-20C8051F330-GM 166CLM8051F500-IQ TQFP-48C8051F500-IQ 167CLM8051F500-IM VFQFN-48C8051F500-IM 168CLM8051F502-IQ LQFP-32C8051F502-IQ 169CLM8051F502-IM QFN-32C8051F502-IM170CLM08D1500CIYB/NOPB HLQFP-128ADC08D1500CIYB/NOPB 171CLM083000CIYB/NOPB HLQFP-128ADCADC083000CIYB/NOPB 172CLM10AQ190AVTPY EBGA-38010位5GSPS ADC EV10AQ190AVTPY 173CLM9680BCPZ-1250LFCSP-64双通道14位1GSPS ADC AD9680BCPZ-1250174CLM9739BBCZ BGA-16014位、2.5 GSPS、RF数模AD9739BBCZ 175CLM9779ABSVZ TQFP-100双通道16位1GSPS DAC AD9779ABSVZ 176CLM12DS130AVZPY FPBGA-19612位3GSPS DAC EV12DS130AVZPY 177CLM12DS460AVZP FPBGA-19612位6.4GSPS DAC EV12DS460AVZP 178CLM9434BCPZ-370LFCSP-5612位370MSPS ADC AD9434BCPZ-370179CLM9434BCPZ-500LFCSP-5612位500MSPS ADC AD9434BCPZ-500180CLM4149IRGZTVQFN-4814位250MSPS ADCADS4149IRGZT产品手册10序号产品型号封装形式产品概述兼容型号181CLM9467BCPZ-200LFCSP-7216位200MSPS ADC AD9467BCPZ-200182CLM9467BCPZ-250LFCSP-7216位250MSPS ADC AD9467BCPZ-250183CLM9656BCPZ-125LFCSP-56四通道16位125MSPS ADC AD9656BCPZ-125184CLM9245BCPZ-40LFCSP-3214位40MSPS ADC AD9245BCPZ-40185CLM9245BCPZ-65LFCSP-3214位65MSPS ADC AD9245BCPZ-80186CLM9245BCPZ-80LFCSP-3214位80MSPS ADC AD9245BCPZ-80187CLM9783BCPZ LFCSP-72双通道16位500MSPS DAC AD9783BCPZ 188CLM7656BSTZ-REEL LQFP-64六通道16位250KSPS ADC AD7656BSTZ-REEL 189CLM7960BCPZLFCSP-3218位2MSPS ADC AD7960BCPZ190CLM128S102CIMTX/NOPB TSSOP-1612位1MSPS ADC ADC128S102CIMTX/NOPB 191CLM5638IDR SOIC-8DACTLV5638IDR 192CLM7606BSTZ LQFP-64AD7606BSTZ 193CLM9625BBPZ-2.5BGA-19612位2.6GSPS ADC AD9625BBPZ-2.5194CLM9164BBCZ BGA-16516位12GSPS DAC AD9164BBCZ 195CLM9154BCPZ LFCSP-88四通道16位2.4GSPS DAC AD9154BCPZ 196CLM2160IUK#PBF QFN-4816位25MSPS ADC LTC2160IUK#PBF 197CLM9652BBCZ-310BGA-144双通道16位310MSPS ADC AD9652BBCZ-310198CLM7779ACPZ-RL LFCSP-6424位16KSPS ADC AD7779ACPZ-RL 199CLM9208BBPZ-3000BGA-196双通道14位3GSPS ADCAD9208BBPZ-3000200CLM320VC33PGE120LQFP-144TMS320VC33PGE120产品手册序号产品型号封装形式产品概述兼容型号201CLM320VC33PGEA120LQFP-144TMS320VC33PGEA120 202CLM320VC33PGE150LQFP-144TMS320VC33PGE150203CLM320VC5402PGE100LQFP-144TMS320VC5402PGE100 204CLM320F28335PGFA LQFP-176TMS320F28335PGFA205CLM320LF2406APZA LQFP-100TMS320LF2406APZA206CLM320LF2406APZS LQFP-100TMS320LF2406APZS207CLM320LF2407APGES LQFP-144TMS320LF2407APGES208CLM320LF2407APGEA LQFP-144TMS320LF2407APGEA 209CLM320C6713BPYP200HLQFP-208TMS320C6713BPYP200 210CLM320C6713BZDP225BGA-272TMS320C6713BZDP225 211CLM320C6713BGDP225BGA-272TMS320C6713BGDP225 212CLM320C6713BZDP300BGA-272TMS320C6713BZDP300 213CLM320C6713BGDG300BGA-272TMS320C6713BGDP30011邮箱：*******************。
高精度频率测量模块开发与设计
高精度频率测量模块开发与设计梁景棠【摘要】分析了单片机测量频率原理及过程,提出了单片机测量频率的可行方案.对各个子模块设计进行了详细的方案论证和比较.软件设计完成了程序模块规划、主程序模块和各个接口模块的设计与编程,给出了采集信号、数据处理及LED数码管显示软件设计详细流程.【期刊名称】《电气开关》【年(卷),期】2015(053)005【总页数】4页(P55-58)【关键词】频率测量;单片机;软件设计;模块设计【作者】梁景棠【作者单位】惠州供电局,广东惠州 516001【正文语种】中文【中图分类】TM935频率测量所能达到的精度，主要取决于作为标准器使用的频率源的精度以及所使用的测量设备和测量方法。
目前，国内外使用测频的方法有很多，有直接测频法、内插法、游标法、时间—电压变化法、多周期同步法、频率倍增法、频差倍增法以及相位比较法等等。
无论使用哪种测量方法，频率测量都是基于以下两种基本方法的。
一种是测频法,即将被测信号加到计数器的计数输入端上,计数器在标准时间Ts1内进行计数，所得的计数值N1与被测信号的频率fx1有如下关系:fx1=N1/Ts1=N1fs1另一种方法是测周法，该方法是将标准频率信号fx2送到计数器的计数输入端，而让被测频率信号控制计数器的计数时间，所得的计数值N2与fx2有如下关系：fx2=fs2/N2无论用哪种方法进行频率测量，主要误差源都是由于计数器只能进行整数计数而引起的±1 误差ε=ΔN/N对于测频法有：ε1=ΔN1/N1=±1/N1=±1/(Ns1fx1)=±fs1/fx1对于测周法有：ε=ΔN2/N2=±1/N2=±fx2/fs2=±Ts2fx2可见在同样的Ts 下，测频法在fx1的低频端误差远大于高频端，而测周法在fx2的高频率的误差远大于低频端，理论研究表明，如进行n 次重复测量取平均，则±1 误差会减小n倍。
MAX485
针对RS-232-C的不足，出现了一些新的接口标准，RS－485的电气标准就是其中的一种。
RS－485是美国电气工业联合会(EIA)制定的利用平衡双绞线作传输线的多点通讯标准。
它采用差分信号进行传输；最大传输距离可以达到1.2 km；最大可连接32个驱动器和收发器；接收器最小灵敏度可达±200 mV；最大传输速率可达2.5 Mb/s。
由此可见，RS－485协议正是针对远距离、高灵敏度、多点通讯制定的标准。
RS-485具有以下特点：1）RS-485的电气特性：逻辑“1”以两线间的电压差为+（2―6）V表示；逻辑“0”以两线间的电压差为-（2―6）V表示。
接口信号电平比RS-232-C降低了，就不易损坏接口电路的芯片，且该电平与TTL电平兼容，可方便与TTL 电路连接。
2）RS-485的数据最高传输速率为10Mbps3）RS-485接口是采用平衡驱动器和差分接收器的组合，抗共模干能力增强，即抗噪声干扰性好。
4）RS-485接口的最大传输距离标准值为4000英尺，实际上可达3000米，另外RS-232-C接口在总线上只允许连接1个收发器，即单站能力。
而RS-485接口在总线上是允许连接多达128个收发器。
即具有多站能力,这样用户可以利用单一的RS-485接口方便地建立起设备网络。
MAX485接口芯片是Maxim公司的一种RS－485芯片。
采用单一电源+5 V工作，额定电流为300 μA，采用半双工通讯方式。
它完成将TTL电平转换为RS－485电平的功能。
其引脚结构图如图1所示。
从图中可以看出,MAX485芯片的结构和引脚都非常简单,内部含有一个驱动器和接收器。
RO和DI端分别为接收器的输出和驱动器的输入端，与单片机连接时只需分别与单片机的RXD和TXD相连即可；/RE和DE端分别为接收和发送的使能端，当/RE为逻辑0时，器件处于接收状态；当DE为逻辑1时，器件处于发送状态，因为MAX485工作在半双工状态，所以只需用单片机的一个管脚控制这两个引脚即可；A端和B端分别为接收和发送的差分信号端,当A引脚的电平高于B时，代表发送的数据为1；当A的电平低于B端时，代表发送的数据为0。
电厂变压器套管绝缘性能在线监测技术分析
电厂变压器套管绝缘性能在线监测技术分析摘要：套管是电厂变压器的附件重要组成单元之一，其为变压器与高压母线的桥梁。
套管在运行过程中一旦出现绝缘性能故障，将导致电力系统停运，造成严重变压器事故。
基于此，本文在简单介绍在线监测技术原理的基础上，分析了电厂变压器套管绝缘性能检测方法，并对电厂变压器套管绝缘性能在线监测方案进行了深入研究，以期能够提升套管绝缘性能实时在线监测的精确性，确保套管安全运行。
关键词：系统变压器；绝缘性能；套管前言电厂电气设备在长期运行过程中将普遍面临绝缘老化的问题，而绝缘性能直接引发安全隐患。
针对套管设备的绝缘性能，我国相关企业进行了电气设备预防性试验，针对各种电力设备设置了不同的检修周期与方式。
随着居民生产生活用电量的进一步加大，传统离线检修无法满足电厂需求，在此基础上，在线监测方法有效融合了通信技术、数据处理技术、信号采集技术、智能传感器技术，实现了套管绝缘状态信息的实时获取，降低了监测过程中的人力物力投入，提升了电厂套管运行的安全性。
1电厂变压器套管绝缘性能在线监测原理电厂变压器绝缘套管绝缘性能的在线监测实际上就是对其性能的试验与检测，主要包含分析诊断系统、传感器系统与信号采集系统。
信号采集系统利用传感器获收集变压器绝缘套管状态相关信息并进行相关信息的处理与传递，将信息交递给分析诊断系统；数据信号经过分析诊断系统的处理与诊断，可以得出变压器绝缘套管的绝缘性能状态，评估变压器绝缘套管使用寿命。
2电厂变压器套管绝缘性能检测方法2.1离线检测法离线检测法是一种传统变压器绝缘套管绝缘性能检测方法，在进行监测的过程中，相关工作人员首先要保证变压器绝缘套管停止带电运行，之后人工拆除变压器绝缘套管，加压模拟变压器绝缘套管带电运行状况，从而得到该状态下变压器绝缘套管绝缘状态。
在变压器绝缘套管离线检测法当中，最常用的方法为电桥法，该状态下的运用原理基本等同于变压器绝缘套管带电运行工作原理，因此该方法数据信息更为准确，但是在具体使用时可能会出现变压器绝缘套管两端电压不达标的情况。
MEMORY存储芯片MAX3485ESA中文规格书
General DescriptionDevices in the MAX3483E family (MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E) are ±15kV ESD-protected, +3.3V, low-power transceivers for RS-485 and RS-422 communications. Each device con-tains one driver and one receiver. The MAX3483E and MAX3488E feature slew-rate-limited drivers that minimize EMI and reduce reflections caused by improperly termi-nated cables, allowing error-free data transmission at data rates up to 250kbps. The partially slew-rate-limited MAX3486E transmits up to 2.5Mbps. The MAX3485E, MAX3490E, and MAX3491E transmit at up to 12Mbps.All devices feature enhanced electrostatic discharge (ESD) protection. All transmitter outputs and receiver inputs are protected to ±15kV using IEC 1000-4-2 Air-Gap Discharge, ±8kV using IEC 1000-4-2 Contact Discharge, and ±15kV using the Human Body Model.Drivers are short-circuit current limited and are protected against excessive power dissipation by thermal shutdown circuitry that places the driver outputs into a high-impedance state. The receiver input has a fail-safe feature that guar-antees a logic-high output if both inputs are open circuit.The MAX3488E, MAX3490E, and MAX3491E feature full-duplex communication, while the MAX3483E, MAX3485E, and MAX3486E are designed for half-duplex communication.Applications●Telecommunications●Industrial-Control Local Area Networks●Transceivers for EMI-Sensitive Applications ●Integrated Services Digital Networks ●Packet SwitchingFeatures●ESD Protection for RS-485 I/O Pins•±15kV—Human Body Model•±8kV—IEC 1000-4-2, Contact Discharge •±15kV—IEC 1000-4-2, Air-Gap Discharge ●Operate from a Single +3.3V Supply—No Charge Pump Required ●Interoperable with +5V Logic ●Guaranteed 12Mbps Data Rate(MAX3485E/MAX3490E/MAX3491E)●Slew-Rate Limited for Errorless Data Transmission(MAX3483E/MAX3488E)●2nA Low-Current Shutdown Mode(MAX3483E/MAX3485E/MAX3486E/MAX3491E)●-7V to +12V Common-Mode Input Voltage Range ●Full-Duplex and Half-Duplex Versions Available ●Industry-Standard 75176 Pinout(MAX3483E/MAX3485E/MAX3486E)●Current-Limiting and Thermal Shutdown forDriver Overload ProtectionOrdering Information continued at end of data sheet.PART TEMP . RANGE PIN-PACKAGE MAX3483E CSA 0°C to+70°C 8 SO MAX3483ECPA 0°C to+70°C 8 Plastic DIP MAX3483EESA -40°C to+85°C 8 SO MAX3483EEPA-40°C to+85°C8 Plastic DIPPART NUMBER GUARANTEED DATA RATE (Mbps)SUPPLY VOLTAGE(V)HALF/FULL DUPLEXSLEW-RATE LIMITEDDRIVER/RECEIVER ENABLESHUTDOWN CURRENT (nA)±15kV ESD PROTECTIONPIN COUNTMAX3483E 0.25 3.0 to 3.6Half Yes Yes 2Yes 8MAX3485E 12Half No Yes 2Yes 8MAX3486E 2.5Half Yes Yes 2Yes 8MAX3488E 0.25Full Yes No —Yes 8MAX3490E 12Full No No —Yes 8MAX3491E12FullNoYes2Yes14MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E3.3V-Powered, ±15kV ESD-Protected,12Mbps and Slew-Rate-Limited True RS-485/RS-422 TransceiversSelector GuideOrdering InformationFigure 1. MAX3483E/MAX3485E/MAX3486E Pin Configuration and Typical Operating CircuitFigure 2. MAX3488E/MAX3490E Pin Configuration and Typical Operating CircuitFigure 3. MAX3491E Pin Configuration and Typical Operating CircuitMAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E3.3V-Powered, ±15kV ESD-Protected,12Mbps and Slew-Rate-Limited True RS-485/RS-422 TransceiversFigure 4. Driver V OD and V OC Figure 5. Driver V OD with Varying Common-Mode VoltageNote 4: The input pulse is supplied by a generator with the following characteristics: f = 250kHz, 50% duty cycle, t r ≤ 6.0ns, Z O = 50Ω.Note 5: C L includes probe and stray capacitance.Figure 11. Receiver Propagation DelayFigure 12. Receiver Enable and Disable TimesMAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E 3.3V-Powered, ±15kV ESD-Protected,12Mbps and Slew-Rate-Limited True RS-485/RS-422 Transceivers。
MEMORY存储芯片MAX487EESA+T中文规格书
±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 TransceiversSWITCHING CHARACTERISTICS—MAX483E, MAX487E/MAX488E/MAX489E (V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)SWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487E(continued)(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)2251000Figures 11 and 13, C L = 100pF, S2 closedFigures 11 and 13, C L = 100pF, S1 closedFigures 9 and 15, C L = 15pF, S2 closed,A -B = 2VCONDITIONSns 45100t ZH(SHDN)Driver Enable from Shutdown to Output High (MAX481E)ns Figures 9 and 15, C L = 15pF, S1 closed,B - A = 2V t ZL(SHDN)Receiver Enable from Shutdown to Output Low (MAX481E)ns 45100t ZL(SHDN)Driver Enable from Shutdown to Output Low (MAX481E)ns 2251000t ZH(SHDN)Receiver Enable from Shutdown to Output High (MAX481E)UNITS MIN TYP MAX SYMBOL PARAMETER t PLH t SKEW Figures 10 and 12, R DIFF = 54Ω,C L1= C L2= 100pF t PHL Figures 10 and 12, R DIFF = 54Ω,C L1= C L2= 100pF Driver Input to OutputDriver Output Skew to Outputns 20800ns ns 2000MAX483E/MAX487E, Figures 11 and 13,C L = 100pF, S2 closed t ZH(SHDN)Driver Enable from Shutdown to Output High 2502000ns 2500MAX483E/MAX487E,Figures 9 and 15,C L = 15pF, S1 closed t ZL(SHDN)Receiver Enable from Shutdownto Output Lowns 2500MAX483E/MAX487E,Figures 9 and 15,C L = 15pF, S2 closed t ZH(SHDN)Receiver Enable from Shutdown to Output High ns 2000MAX483E/MAX487E, Figures 11 and 13,C L = 100pF, S1 closed t ZL(SHDN)Driver Enable from Shutdown to Output Low ns 50200600MAX483E/MAX487E (Note 5) t SHDNTime to Shutdown t PHLt PLH , t PHL < 50% of data period Figures 9 and 15, C RL = 15pF, S2 closed Figures 9 and 15, C RL = 15pF, S1 closed Figures 9 and 15, C RL = 15pF, S2 closed Figures 9 and 15, C RL = 15pF, S1 closed Figures 11 and 13, C L = 15pF, S2 closed Figures 10 and 14, R DIFF = 54Ω,C L1= C L2= 100pF Figures 11 and 13, C L = 15pF, S1 closed Figures 11 and 13, C L = 100pF, S1 closed Figures 11 and 13, C L = 100pF, S2 closed CONDITIONS kbps 250f MAX2508002000Maximum Data Rate ns 2550t HZReceiver Disable Time from High ns 25080020002550t LZReceiver Disable Time from Low ns 2550t ZHReceiver Enable to Output High ns 2550t ZLReceiver Enable to Output Low ns ns 1003003000t HZ t SKDDriver Disable Time from HighI t PLH - t PHL I Differential Receiver Skew Figures 10 and 14, R DIFF = 54Ω,C L1= C L2= 100pF ns 3003000t LZ Driver Disable Time from Lowns 2502000t ZL Driver Enable to Output Lowns Figures 10 and 12, R DIFF = 54Ω,C L1= C L2= 100pF ns 2502000t R , t F 2502000Driver Rise or Fall Timens t PLHReceiver Input to Output 2502000t ZH Driver Enable to Output HighUNITS MIN TYP MAX SYMBOL PARAMETERMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E4±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 TransceiversFigure 6. IEC1000-4-2 ESD Test ModelFigure 8. Driver DC Test LoadFigure 7. IEC1000-4-2 ESD Generator Current WaveformFigure 9. Receiver Timing Test LoadFigure 4. Human Body ESD Test ModelFigure 5. Human Body Model Current Waveform MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E10。
RS－485低功耗收发器MAX485E
RS－485低功耗收发器MAX485E
左森
【期刊名称】《电子世界》
【年(卷),期】2002(000)002
【摘要】@@ 单片机串行口的协议信号为RS-232信号，可以利用RS-232串行
通信协议直接进行串行通信。
但RS-232协议的支持的传输距离近，不超过50m。
RS-485串行通信协议支持的传输距离远，达1200m，且抗干扰能力强，数据传
输速率高，所以，将单片机串行口的RS-232协议信号转换为RS-485协议信号，便可实现单片机的远距离通信。
利用MAX485E芯片，可以将单片机串行口的
RS232协议信号转换为RS-485信号，进行远距离通信。
【总页数】1页(P41)
【作者】左森
【作者单位】无
【正文语种】中文
【中图分类】TN8
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MEMORY存储芯片MAX485ESA中文规格书
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX UNITS
MAX488/MAX489, DE, DI, RE = 0V or VCC
120
250
MAX490/MAX491, DE, DI, RE = 0V or VCC
300
500
No-Load Supply Current (Note 3)
35
250
mA
Driver Short-Circuit Current, VO = Low
IOSD2 -7V ≤ VO ≤12V (Note 4)
35
250
mA
Receiver Short-Circuit Current
IOSR 0V ≤ VO ≤ VCC
7
95
mA
SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487
o For Multiple Transceiver Applications MAX3030E–MAX3033E: ±15kV ESD-Protected, +3.3V, Quad RS-422 Transmitters
o For Fail-Safe Applications MAX3080–MAX3089: Fail-Safe, High-Speed (10Mbps), Slew-Rate-Limited RS-485/RS-422 Transceivers
MAX481
Half
MAX483
Half
MAX485
Half
MAX487
Half
MAX488
MAX488ECSA中文资料
General DescriptionThe MAX481E, MAX483E, MAX485E, MAX487E–MAX491E, and MAX1487E are low-power transceivers for RS-485 and RS-422 communications in harsh environ-ments. Each driver output and receiver input is protected against ±15kV electro-static discharge (ESD) shocks,without latchup. These parts contain one driver and one receiver. The MAX483E, MAX487E, MAX488E, and MAX489E feature reduced slew-rate drivers that minimize EMI and reduce reflections caused by improperly termi-nated cables, thus allowing error-free data transmission up to 250kbps. The driver slew rates of the MAX481E,MAX485E, MAX490E, MAX491E, and MAX1487E are not limited, allowing them to transmit up to 2.5Mbps.These transceivers draw as little as 120µA supply cur-rent when unloaded or when fully loaded with disabled drivers (see Selector Guide ). Additionally, the MAX481E,MAX483E, and MAX487E have a low-current shutdown mode in which they consume only 0.5µA. All parts oper-ate from a single +5V supply.Drivers are short-circuit current limited, and are protected against excessive power dissipation by thermal shutdown circuitry that places their outputs into a high-impedance state. The receiver input has a fail-safe feature that guar-antees a logic-high output if the input is open circuit.The MAX487E and MAX1487E feature quarter-unit-load receiver input impedance, allowing up to 128 trans-ceivers on the bus. The MAX488E–MAX491E are designed for full-duplex communications, while the MAX481E, MAX483E, MAX485E, MAX487E, and MAX1487E are designed for half-duplex applications.For applications that are not ESD sensitive see the pin-and function-compatible MAX481, MAX483, MAX485,MAX487–MAX491, and MAX1487.ApplicationsLow-Power RS-485 Transceivers Low-Power RS-422 Transceivers Level TranslatorsTransceivers for EMI-Sensitive Applications Industrial-Control Local Area NetworksNext-Generation Device Features♦For Fault-Tolerant Applications:MAX3430: ±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V, RS-485 TransceiverMAX3080–MAX3089: Fail-Safe, High-Speed (10Mbps), Slew-Rate-Limited, RS-485/RS-422Transceivers ♦For Space-Constrained Applications:MAX3460–MAX3464: +5V, Fail-Safe, 20Mbps,Profibus, RS-485/RS-422 TransceiversMAX3362: +3.3V, High-Speed, RS-485/RS-422Transceiver in a SOT23 PackageMAX3280E–MAX3284E: ±15kV ESD-Protected,52Mbps, +3V to +5.5V, SOT23, RS-485/RS-422True Fail-Safe ReceiversMAX3030E–MAX3033E: ±15kV ESD-Protected,+3.3V, Quad RS-422 Transmitters ♦For Multiple Transceiver Applications:MAX3293/MAX3294/MAX3295: 20Mbps, +3.3V,SOT23, RS-485/RS-422 Transmitters ♦For Fail-Safe Applications:MAX3440E–MAX3444E: ±15kV ESD-Protected,±60V Fault-Protected, 10Mbps, Fail-Safe RS-485/J1708 Transceivers ♦For Low-Voltage Applications:MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E: +3.3V Powered, ±15kV ESD-Protected, 12Mbps, Slew-Rate-Limited, True RS-485/RS-422 TransceiversMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 Transceivers________________________________________________________________Maxim Integrated Products 1Ordering Information19-0410; Rev 4; 10/03For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .Ordering Information continued at end of data sheet.Selector Guide appears at end of data sheet .M A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers2_______________________________________________________________________________________Supply Voltage (V CC ) (12V)Control Input Voltage (–R —E –, DE)...................-0.5V to (V CC + 0.5V)Driver Input Voltage (DI).............................-0.5V to (V CC + 0.5V)Driver Output Voltage (Y, Z; A, B)..........................-8V to +12.5V Receiver Input Voltage (A, B).................................-8V to +12.5V Receiver Output Voltage (RO)....................-0.5V to (V CC + 0.5V)Continuous Power Dissipation (T A = +70°C)8-Pin Plastic DIP (derate 9.09mW/°C above +70°C)....727mW14-Pin Plastic DIP (derate 10.00mW/°C above +70°C)..800mW 8-Pin SO (derate 5.88mW/°C above +70°C).................471mW 14-Pin SO (derate 8.33mW/°C above +70°C)...............667mW Operating Temperature RangesMAX4_ _C_ _/MAX1487EC_ A.............................0°C to +70°C MAX4__E_ _/MAX1487EE_ A...........................-40°C to +85°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering, 10sec).............................+300°CDC ELECTRICAL CHARACTERISTICS(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)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.ABSOLUTE MAXIMUM RATINGSPARAMETERSYMBOL MINTYPMAX UNITS Driver Common-Mode Output VoltageV OC 3V Change in Magnitude of Driver Differential Output Voltage for Complementary Output States ∆V OD 0.2V Change in Magnitude of Driver Common-Mode Output Voltage for Complementary Output States ∆V OD 0.2V Input High Voltage V IH 2.0V Input Low Voltage V IL 0.8V Input CurrentI IN1±2µADifferential Driver Output (no load)V OD15V 2V Differential Driver Output (with load)V OD2 1.551.0-0.8mA0.25mA -0.2Receiver Differential Threshold Voltage-0.20.2V Receiver Input Hysteresis ∆V TH 70mV Receiver Output High Voltage V OH 3.5Receiver Output Low Voltage V OL 0.4V Three-State (high impedance)Output Current at ReceiverI OZR±1µA 12k ΩCONDITIONSDE = 0V;V CC = 0V or 5.25V,all devices except MAX487E/MAX1487E R = 27Ωor 50Ω, Figure 8R = 27Ωor 50Ω, Figure 8R = 27Ωor 50Ω, Figure 8DE, DI, –R —E–MAX487E/MAX1487E,DE = 0V, V CC = 0V or 5.25VDE, DI, –R —E–DE, DI, –R —E–-7V ≤V CM ≤12V V CM = 0VI O = -4mA, V ID = 200mV I O = 4mA, V ID = -200mV R = 50Ω(RS-422)0.4V ≤V O ≤2.4VR = 27Ω(RS-485), Figure 8-7V ≤V CM ≤12V, all devices except MAX487E/MAX1487EReceiver Input Resistance R IN-7V ≤V CM ≤12V, MAX487E/MAX1487E48k ΩV TH I IN2Input Current (A, B)V IN = 12V V IN = -7V V IN = 12V V IN = -7VVMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 TransceiversSWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487EDC ELECTRICAL CHARACTERISTICS (continued)(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)M A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers4_______________________________________________________________________________________SWITCHING CHARACTERISTICS—MAX483E, MAX487E/MAX488E/MAX489E(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)SWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487E(continued)(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)2251000Figures 11 and 13, C L = 100pF, S2 closed Figures 11 and 13, C L = 100pF, S1 closed Figures 9 and 15, C L = 15pF, S2 closed,A - B = 2VCONDITIONSns 45100t ZH(SHDN)Driver Enable from Shutdown toOutput High (MAX481E)nsFigures 9 and 15, C L = 15pF, S1 closed,B - A = 2Vt ZL(SHDN)Receiver Enable from Shutdownto Output Low (MAX481E)ns 45100t ZL(SHDN)Driver Enable from Shutdown toOutput Low (MAX481E)ns 2251000t ZH(SHDN)Receiver Enable from Shutdownto Output High (MAX481E)UNITS MINTYP MAX SYMBOLPARAMETERt PLH t SKEW Figures 10 and 12, R DIFF = 54Ω,C L1= C L2= 100pFt PHL Figures 10 and 12, R DIFF = 54Ω,C L1= C L2= 100pFDriver Input to Output Driver Output Skew to Output ns 20800ns ns 2000MAX483E/MAX487E, Figures 11 and 13,C L = 100pF, S2 closedt ZH(SHDN)Driver Enable from Shutdown to Output High2502000ns2500MAX483E/MAX487E, Figures 9 and 15,C L = 15pF, S1 closedt ZL(SHDN)Receiver Enable from Shutdown to Output Lowns 2500MAX483E/MAX487E, Figures 9 and 15,C L = 15pF, S2 closedt ZH(SHDN)Receiver Enable from Shutdown to Output Highns 2000MAX483E/MAX487E, Figures 11 and 13,C L = 100pF, S1 closedt ZL(SHDN)Driver Enable from Shutdown to Output Lowns 50200600MAX483E/MAX487E (Note 5)t SHDN Time to Shutdownt PHL t PLH , t PHL < 50% of data period Figures 9 and 15, C RL = 15pF, S2 closed Figures 9 and 15, C RL = 15pF, S1 closed Figures 9 and 15, C RL = 15pF, S2 closed Figures 9 and 15, C RL = 15pF, S1 closed Figures 11 and 13, C L = 15pF, S2 closed Figures 10 and 14, R DIFF = 54Ω,C L1= C L2= 100pFFigures 11 and 13, C L = 15pF, S1 closed Figures 11 and 13, C L = 100pF, S1 closed Figures 11 and 13, C L = 100pF, S2 closed CONDITIONSkbps 250f MAX 2508002000Maximum Data Rate ns 2550t HZ Receiver Disable Time from High ns 25080020002550t LZ Receiver Disable Time from Low ns 2550t ZH Receiver Enable to Output High ns 2550t ZL Receiver Enable to Output Low ns ns 1003003000t HZ t SKD Driver Disable Time from High I t PLH - t PHL I DifferentialReceiver SkewFigures 10 and 14, R DIFF = 54Ω,C L1= C L2= 100pFns 3003000t LZ Driver Disable Time from Low ns 2502000t ZL Driver Enable to Output Low ns Figures 10 and 12, R DIFF = 54Ω,C L1= C L2= 100pFns 2502000t R , t F 2502000Driver Rise or Fall Time ns t PLH Receiver Input to Output2502000t ZH Driver Enable to Output High UNITS MIN TYP MAX SYMBOL PARAMETERMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers_______________________________________________________________________________________505101520253035404550OUTPUT CURRENT vs.RECEIVER OUTPUT LOW VOLTAGEM A X 481E -01OUTPUT LOW VOLTAGE (V)O U T P U T C U R R E N T (m A )1.52.02.51.00.50.10.20.30.40.50.60.70.80.9-60-2060RECEIVER OUTPUT LOW VOLTAGEvs. TEMPERATURETEMPERATURE (°C)O U T P U T L O W V O L T A G E (V )20100-4040800-5-10-15-20-251.53.0OUTPUT CURRENT vs.RECEIVER OUTPUT HIGH VOLTAGEM A X 481E -02OUTPUT HIGH VOLTAGE (V)O U T P U T C U R R E N T (m A )5.04.54.02.02.53.53.03.23.43.63.84.04.24.44.64.8-60-2060RECEIVER OUTPUT HIGH VOLTAGEvs. TEMPERATURETEMPERATURE (°C)O U T P U T H I G H V O L T A G E (V )20100-4040800102030405060708090DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGEM A X 481E -05DIFFERENTIAL OUTPUT VOLTAGE (V)O U T P U T C U R R E N T (m A )1.52.0 2.53.0 3.54.0 4.51.00.50__________________________________________Typical Operating Characteristics(V CC = 5V, T A = +25°C, unless otherwise noted.)NOTES FOR ELECTRICAL/SWITCHING CHARACTERISTICSNote 1:All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to deviceground unless otherwise specified.Note 2:All typical specifications are given for V CC = 5V and T A = +25°C.Note 3:Supply current specification is valid for loaded transmitters when DE = 0V.Note 4:Applies to peak current. See Typical Operating Characteristics.Note 5:The MAX481E/MAX483E/MAX487E are put into shutdown by bringing –R —E –high and DE low. If the inputs are in this state forless than 50ns, the parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 600ns, the parts are guaranteed to have entered shutdown. See Low-Power Shutdown Mode section.M A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers6___________________________________________________________________________________________________________________Typical Operating Characteristics (continued)(V CC = 5V, T A = +25°C, unless otherwise noted.)1.52.32.22.12.01.91.81.71.6-60-2060DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURETEMPERATURE (°C)D I F FE R E N T I A L O U T P U T V O L T A G E (V )20100-404080020406080100120140OUTPUT CURRENT vs. DRIVER OUTPUT LOW VOLTAGEM A X 481E -07OUTPUT LOW VOLTAGE (V)O U T P U T C U R R E N T (m A )246810120-10-20-30-40-50-60-70-80-90-100-8-2OUTPUT CURRENT vs. DRIVER OUTPUT HIGH VOLTAGEM A X 481E -08OUTPUT HIGH VOLTAGE (V)O U T P U T C U R R E N T (m A )642-6-400100200300400500600-60-2060MAX481E/MAX485E/MAX490E/MAX491E SUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T (µA )20100-4040800100200300400500600-60-2060MAX483E/MAX487E–MAX489E SUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T (µA )20100-404080100200300400500600-60-2060MAX1487ESUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T (µA )20100-404080±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 Transceivers_______________________________________________________________________________________7MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E______________________________________________________________Pin DescriptionM A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers8_________________________________________________________________________________________________Function Tables (MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E) Table 1. Transmitting__________Applications Information The MAX481E/MAX483E/MAX485E/MAX487E–MAX491E and MAX1487E are low-power transceivers for RS-485 and RS-422 communications. These “E” versions of the MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 provide extra protection against ESD. The rugged MAX481E, MAX483E, MAX485E, MAX497E–MAX491E, and MAX1487E are intended for harsh envi-ronments where high-speed communication is important. These devices eliminate the need for transient suppres-sor diodes and the associated high capacitance loading. The standard (non-“E”) MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 are recommended for applications where cost is critical.The MAX481E, MAX485E, MAX490E, MAX491E, and MAX1487E can transmit and receive at data rates up to 2.5Mbps, while the MAX483E, MAX487E, MAX488E, and MAX489E are specified for data rates up to 250kbps. The MAX488E–MAX491E are full-duplex transceivers, while the MAX481E, MAX483E, MAX487E, and MAX1487E are half-duplex. In addition, driver-enable (DE) and receiver-enable (RE) pins are included on the MAX481E, MAX483E, MAX485E, MAX487E, MAX489E, MAX491E, and MAX1487E. When disabled, the driver and receiver outputs are high impedance.±15kV ESD Protection As with all Maxim devices, ESD-protection structures are incorporated on all pins to protect against electro-static discharges encountered during handling and assembly. The driver outputs and receiver inputs have extra protection against static electricity. Maxim’s engi-neers developed state-of-the-art structures to protect these pins against ESD of ±15kV without damage. The ESD structures withstand high ESD in all states: normal operation, shutdown, and powered down. After an ESD event, Maxim’s MAX481E, MAX483E, MAX485E, MAX487E–MAX491E, and MAX1487E keep working without latchup.ESD protection can be tested in various ways; the transmitter outputs and receiver inputs of this product family are characterized for protection to ±15kV using the Human Body Model.Other ESD test methodologies include IEC10004-2 con-tact discharge and IEC1000-4-2 air-gap discharge (for-merly IEC801-2).ESD Test Conditions ESD performance depends on a variety of conditions. Contact Maxim for a reliability report that documents test set-up, test methodology, and test results.Human Body Model Figure 4 shows the Human Body Model, and Figure 5 shows the current waveform it generates when dis-charged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of inter-est, which is then discharged into the test device through a 1.5kΩresistor.IEC1000-4-2 The IEC1000-4-2 standard covers ESD testing and per-formance of finished equipment; it does not specifically refer to integrated circuits (Figure 6).MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers_______________________________________________________________________________________9M A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers10______________________________________________________________________________________Figure 8. Driver DC Test LoadFigure 9. Receiver Timing Test LoadMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers______________________________________________________________________________________11Figure 10. Driver/Receiver Timing Test Circuit Figure 11. Driver Timing Test LoadFigure 12. Driver Propagation DelaysFigure 13. Driver Enable and Disable Times (except MAX488E and MAX490E)Figure 14. Receiver Propagation DelaysFigure 15. Receiver Enable and Disable Times (except MAX488E and MAX490E)M A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers12______________________________________________________________________________________The major difference between tests done using the Human Body Model and IEC1000-4-2 is higher peak current in IEC1000-4-2, because series resistance is lower in the IEC1000-4-2 model. Hence, the ESD with-stand voltage measured to IEC1000-4-2 is generally lower than that measured using the Human Body Model. Figure 7 shows the current waveform for the 8kV IEC1000-4-2 ESD contact-discharge test.The air-gap test involves approaching the device with a charged probe. The contact-discharge method connects the probe to the device before the probe is energized.Machine ModelThe Machine Model for ESD tests all pins using a 200pF storage capacitor and zero discharge resis-tance. Its objective is to emulate the stress caused by contact that occurs with handling and assembly during manufacturing. Of course, all pins require this protec-tion during manufacturing—not just inputs and outputs.Therefore,after PC board assembly,the Machine Model is less relevant to I/O ports.MAX487E/MAX1487E:128 Transceivers on the BusThe 48k Ω, 1/4-unit-load receiver input impedance of the MAX487E and MAX1487E allows up to 128 transceivers on a bus, compared to the 1-unit load (12k Ωinput impedance) of standard RS-485 drivers (32 transceivers maximum). Any combination of MAX487E/MAX1487E and other RS-485 transceivers with a total of 32 unit loads or less can be put on the bus. The MAX481E,MAX483E, MAX485E, and MAX488E–MAX491E have standard 12k Ωreceiver input impedance.MAX483E/MAX487E/MAX488E/MAX489E:Reduced EMI and Reflections The MAX483E and MAX487E–MAX489E are slew-rate limited, minimizing EMI and reducing reflections caused by improperly terminated cables. Figure 16shows the driver output waveform and its Fourier analy-sis of a 150kHz signal transmitted by a MAX481E,MAX485E, MAX490E, MAX491E, or MAX1487E. High-frequency harmonics with large amplitudes are evident.Figure 17 shows the same information displayed for a MAX483E, MAX487E, MAX488E, or MAX489E transmit-ting under the same conditions. Figure 17’s high-fre-quency harmonics have much lower amplitudes, and the potential for EMI is significantly reduced.Low-Power Shutdown Mode (MAX481E/MAX483E/MAX487E)A low-power shutdown mode is initiated by bringing both RE high and DE low. The devices will not shut down unless both the driver and receiver are disabled.In shutdown, the devices typically draw only 0.5µA of supply current.RE and DE may be driven simultaneously; the parts are guaranteed not to enter shutdown if RE is high and DE is low for less than 50ns. If the inputs are in this state for at least 600ns, the parts are guaranteed to enter shutdown.For the MAX481E, MAX483E, and MAX487E, the t ZH and t ZL enable times assume the part was not in the low-power shutdown state (the MAX485E, MAX488E–MAX491E, and MAX1487E can not be shut down). The t ZH(SHDN)and t ZL(SHDN)enable times assume the parts were shut down (see Electrical Characteristics ).500kHz/div0Hz5MHz 10dB/div Figure 16. Driver Output Waveform and FFT Plot ofMAX485E/MAX490E/MAX491E/MAX1487E Transmitting a 150kHz Signal500kHz/div0Hz5MHz10dB/divFigure 17. Driver Output Waveform and FFT Plot ofMAX483E/MAX487E–MAX489E Transmitting a 150kHz SignalIt takes the drivers and receivers longer to become enabled from the low-power shutdown state (t ZH(SHDN), t ZL(SHDN)) than from the operating mode (t ZH, t ZL). (The parts are in operating mode if the RE, DE inputs equal a logical 0,1 or 1,1 or 0, 0.)Driver Output Protection Excessive output current and power dissipation caused by faults or by bus contention are prevented by two mechanisms. A foldback current limit on the output stage provides immediate protection against short circuits over the whole common-mode voltage range (see Typical Operating Characteristics). In addition, a thermal shut-down circuit forces the driver outputs into a high-imped-ance state if the die temperature rises excessively.Propagation Delay Many digital encoding schemes depend on the differ-ence between the driver and receiver propagation delay times. Typical propagation delays are shown in Figures 19–22 using Figure 18’s test circuit.The difference in receiver delay times, t PLH- t PHL, is typically under 13ns for the MAX481E, MAX485E, MAX490E, MAX491E, and MAX1487E, and is typically less than 100ns for the MAX483E and MAX487E–MAX489E.The driver skew times are typically 5ns (10ns max) for the MAX481E, MAX485E, MAX490E, MAX491E, and MAX1487E, and are typically 100ns (800ns max) for the MAX483E and MAX487E–MAX489E.Typical Applications The MAX481E, MAX483E, MAX485E, MAX487E–MAX491E, and MAX1487E transceivers are designed for bidirectional data communications on multipoint bus transmission lines. Figures 25 and 26 show typical net-work application circuits. These parts can also be used as line repeaters, with cable lengths longer than 4000 feet. To minimize reflections, the line should be terminated at both ends in its characteristic impedance, and stub lengths off the main line should be kept as short as possi-ble. The slew-rate-limited MAX483E and MAX487E–MAX489E are more tolerant of imperfect termination. Bypass the V CC pin with 0.1µF.Isolated RS-485 For isolated RS-485 applications, see the MAX253 and MAX1480 data sheets.Line Length vs. Data Rate The RS-485/RS-422 standard covers line lengths up to 4000 feet. Figures 23 and 24 show the system differen-tial voltage for the parts driving 4000 feet of 26AWG twisted-pair wire at 110kHz into 100Ωloads.Figure 18. Receiver Propagation Delay Test CircuitMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers ______________________________________________________________________________________13M A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers14______________________________________________________________________________________25ns/div 5V/divRO B A500mV/div Figure 19. MAX481E/MAX485E/MAX490E/MAX1487E Receiver t PHL25ns/div5V/div ROBA500mV/divFigure 20. MAX481E/MAX485E/MAX490E/MAX491E/MAX1487E Receiver t PLH200ns/div 5V/divRO B A500mV/div Figure 21. MAX483E/MAX487E–MAX489E Receiver t PHL200ns/div5V/div ROBA500mV/divFigure 22. MAX483E/MAX487E–MAX489E Receiver t PLH2µs/div DO 0V0V5V5V -1V 0DIV A - V BFigure 23. MAX481E/MAX485E/MAX490E/MAX491E/MAX1487E System Differential Voltage at 110kHz Driving 4000ft of Cable 2µs/divDO0V0V 5V 5V -1V1V0DIV B - V AFigure 24. MAX483E/MAX1487E–MAX489E System Differential Voltage at 110kHz Driving 4000ft of CableMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers______________________________________________________________________________________15Figure 26. MAX488E–MAX491E Full-Duplex RS-485 NetworkFigure 25. MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E Typical Half-Duplex RS-485 NetworkM A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 Transceivers Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.16____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600©2003 Maxim Integrated ProductsPrinted USAis a registered trademark of Maxim Integrated Products.Package InformationFor the latest package outline information, go to /packages .Ordering Information (continued)Selector GuideChip InformationTRANSISTOR COUNT: 295。
max485的工作原理 与常见问题
max485的工作原理与常见问题1、我想知道MAX485的工作原理，和AT89C51做的接口需要遍程序吗？工作中的工作环境是什么？MAX485是芯片接口的一种类型MAX485接口芯片是Maxim公司的一种RS－485芯片。
采用单一电源+5 V工作，额定电流为300 μA，采用半双工通讯方式。
它完成将TTL 电平转换为RS－485电平的功能。
MAX485芯片的结构和引脚都非常简单,内部含有一个驱动器和接收器。
RO和DI端分别为接收器的输出和驱动器的输入端，与单片机连接时只需分别与单片机的RXD和TXD相连即可；/RE和DE端分别为接收和发送的使能端，当/RE为逻辑0时，器件处于接收状态；当DE为逻辑1时，器件处于发送状态，因为MAX485工作在半双工状态，所以只需用单片机的一个管脚控制这两个引脚即可；A端和B端分别为接收和发送的差分信号端,当A引脚的电平高于B时，代表发送的数据为1；当A的电平低于B端时，代表发送的数据为0。
在与单片机连接时接线非常简单。
只需要一个信号控制MAX485的接收和发送即可。
同时将A和B端之间加匹配电阻，一般可选100Ω的电阻。
可以串行口取电，可以驱动max232与max485实现通信。
没加负载时电压有5.16V，加负载后降制3V左右。
/Soft/UploadSoft/200804/2008041022142701.pdf中文资料的PDF文档，直接打开上面的网址就是参考资料：/Soft/UploadSoft/200804/2008041022142701.pdf2、max485到底能不能直接接入单片机，要怎么接，程序如何？max485接TTL端可以直接接单片机的Txd与Rxd，另一端是Rs232电平的，与PC机连接。
只是电平转换，不用软件驱动。