MAX3051EKA_CAN驱动

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General DescriptionThe MAX3051 interfaces between the CAN protocolcontroller and the physical wires of the bus lines in acontroller area network (CAN). The MAX3051 providesdifferential transmit capability to the bus and differentialreceive capability to the CAN controller. The MAX3051is primarily intended for +3.3V single-supply applicationsthat do not require the stringent fault protection specifiedby the automotive industry (ISO 11898).The MAX3051 features four different modes of operation: high-speed, slope-control, standby, and shutdownmode. High-speed mode allows data rates up to 1Mbps.The slope-control mode can be used to program the slewrate of the transmitter for data rates of up to 500kbps.This reduces the effects of EMI, thus allowing the useof unshielded twisted or parallel cable. In standby mode,the transmitter is shut off and the receiver is pulled high,placing the MAX3051 in low-current mode. In shutdownmode, the transmitter and receiver are switched off.The MAX3051 input common-mode range is from -7V to+12V, exceeding the ISO 11898 specification of -2V to+7V. These features, and the programmable slew-ratelimiting, make the part ideal for nonautomotive, harshenvironments. The MAX3051 is available in 8-pin SO andSOT23 packages and operates over the -40°C to +85°Cextended temperature range.Applications● Printers JetLink● Industrial Control and Networks● Telecom Backplane● Consumer ApplicationsBenefits and Features● Use 3V Microcontroller with Same LDO• Low +3.3V Single-Supply Operation● Common Mode Range Exceeds the ISO11898Standard (-2V to +7V)• Wide -7V to +12V Common-Mode Range● Uses Minimal Board Space• SOT23 Package● Flexible Operation Optimizes Performanceand Power Consumption for Reduced ThermalDissipation• Four Operating Modes• High-Speed Operation Up to 1Mbps• Slope-Control Mode to Reduce EMI (Up to500kbps)• Standby Mode• Low-Current Shutdown Mode● Robust Protection Increases System Reliability• ±12kV Human Body Model ESD Protection• Thermal Shutdown• Current LimitingTypical Operating Circuit at end of data sheet.+Denotes lead(Pb)-free/RoHS-compliant package.T = Tape and reelPART TEMP RANGE PINPACKAGETOPMARKMAX3051ESA+ -40°C to +85°C 8 SO —MAX3051EKA+T -40°C to +85°C 8 SOT23-8 AEKFCANLRXD SHDN1+287RSGND CANHVCCTXDSO/SOT23TOP VIEW3465MAX3051MAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiver19-3274; Rev 3; 2/15Ordering InformationPin ConfigurationVCC to GND ............................................................-0.3V to +6VTXD, RS, SHDN to GND.........................................-0.3V to +6VRXD to GND............................................................-0.3V to +6VCANH, CANL to GND.........................................-7.5V to +12.5VContinuous Power Dissipation (TA = +70°C)8-Pin SO (derate 5.9mW/°C above +70°C).................470mW8-Pin SOT23 (derate 5.1mW/°C above +70°C) .......408.2mWOperating Temperature Range........................... -40°C to +85°CMaximum Junction Temperature .....................................+150°CStorage Temperature Range............................ -65°C to +150°CLead Temperature Range (soldering, 10s)......................+300°CSoldering Temperature (reflow).......................................+260°C(VCC = +3.3V ±5%, RL = 60Ω, CL = 100pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +3.3V andTA = +25°C.) (Note 1)PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITSSupply Current ISDominant 35 70mARecessive 2 5Standby 8 15 µAShutdown Current ISHDN VSHDN = VCC, TXD = VCC or unconnected 1 µAThermal-Shutdown Threshold VTSH +160 °CThermal-Shutdown Hysteresis 25 °CTXD INPUT LEVELSHigh-Level Input Voltage VIH 2 VCC + 0.3V VLow-Level Input Voltage VIL 0.8 VInput Capacitance CIN 5 pFPullup Resistor RINTXD 50 100 kΩCANH, CANL TRANSMITTERRecessive Bus Voltage VCANH,VCANLVTXD = VCC, no load 2 2.3 3 VVTXD = VCC, no load, VRS = VCC(standby mode) -100 +100 mVOff-State Output Leakage -2V < VCANH, VCANL < +7V, SHDN = HIGH -250 +250 µAInput Leakage Current VCC = 0V, VCANH = VCANL = 5V -250 +250 µACANH Output Voltage VCANH VTXD = 0V 2.45 VCANL Output Voltage VCANL VTXD = 0V 1.25 VDifferential Output (VCANH -VCANL)VTXD = 0V 1.5 3.0VVTXD = 0V, RL = 45Ω 1.2 3.0VTXD = VCC, no load -500 +50mVVTXD = VCC, RL = 60Ω -120 +12MAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiverwww.maximintegrated.com Maxim Integrated │ 2Absolute Maximum RatingsStresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at theseor 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 affectdevice reliability.Electrical Characteristics(VCC = +3.3V ±5%, RL = 60Ω, CL = 100pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +3.3V andTA = +25°C.) (Note 1)PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITSCANH Short-Circuit Current ICANHSC-7V ≤ VCANH ≤ 0V -200mAMinimum foldback current -35CANL Short-Circuit Current ICANLSC VCC ≤ VCANL ≤ 12V 200 mARXD OUTPUT LEVELSRXD High Output-Voltage Level VOH I = -1mA 0.8 x VCC VCC VRXD Low Output-Voltage Level VOL I = 4mA 0.4 VDC BUS RECEIVER (VTXD = VCC; CANH and CANL externally driven; -7V ≤ VCANH, VCANL ≤ +12V,unless otherwise specified)Differential Input Voltage(Recessive) VDIFF-7V ≤ VCM ≤ +12V 0.5VVRS = VCC (standby mode) 0.5Differential Input Voltage(Dominant) VDIFFDominant 0.9VVRS = VCC (standby mode) 1.1Differential Input Hysteresis VDIFF(HYST) 20 mVCANH and CANL InputResistance RI 20 50 kΩDifferential Input Resistance RDIFF 40 100 kΩMODE SELECTION (RS)Input Voltage for High Speed VSLP 0.3 x VCC VInput Voltage for Standby VSTBY 0.75 x VCC VSlope-Control Mode Voltage VSLOPE RRS = 25kΩ to 200kΩ 0.4 x VCC 0.6 x VCC VHigh-Speed Mode Current IHS VRS = 0V -500 µASHUTDOWN (SHDN)SHDN Input Voltage High VSHDNH 2 VSHDN Input Voltage Low VSHDNL 0.8 VSHDN Pulldown Resistor RINSHDN 50 100 kΩMAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiverwww.maximintegrated.com Maxim Integrated │ 3Electrical Characteristics (continued)(VCC = +3.3V ±5%, RL = 60Ω, CL = 100pF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +3.3V andTA = +25°C.)Note 1: All currents into device are positive; all currents out of the device are negative. All voltages are referenced to deviceground, unless otherwise noted.Note 2: No other devices on the BUS.Note 3: BUS externally driven.PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITSDelay TXD to Bus Active(Figure 1) tONTXDVRS = 0V (≤ 1Mbps) 50RRS = 25kΩ (≤ 500kbps) 183 nsRRS = 100kΩ (≤ 125kbps) 770Delay TXD to Bus Inactive(Figure 1) tOFFTXDVRS = 0V (≤ 1Mbps) 70RRS = 25kΩ (≤ 500kbps) 226 nsRRS = 100kΩ (≤ 125kbps) 834Delay Bus to Receiver Active(Figure 1) tONRXDVRS = 0V (≤ 1Mbps) 80RRS = 25kΩ (≤ 500kbps) 200 nsRRS = 100kΩ (≤ 125kbps) 730Delay Bus to Receiver Inactive(Figure 1) tOFFRXDVRS = 0V (≤ 1Mbps) 100RRS = 25kΩ (≤ 500kbps) 245 nsRRS = 100kΩ (≤ 125kbps) 800Differential-Output Slew Rate SRVRS = 0V (≤ 1Mbps) 96V/μsRRS = 25kΩ (≤ 500kbps) 12.5RRSS = 100kΩ (≤ 125kbps) 2.9RRS = 200kΩ (≤ 62.5kbps) 1.6Bus Dominant to RXD Active tDRXDL VRS > 0.8 x VCC, standby, Figure 2 1 μsStandby to Receiver Active tSBRXDL BUS dominant, Figure 2 4 μsSHDN to Bus Inactive tOFFSHDN TXD = GND, Figure 3 (Note 2) 1 μsSHDN to Receiver Active tONSHDN BUS dominant, Fi gur e 3 (Note 3) 4 μsSHDN to Standby tSHDNSB Figure 4 20 μsESD Protection Human Body Model ±12 kVMAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiverwww.maximintegrated.com Maxim Integrated │ 4Timing CharacteristicsFigure 1. Timing Diagram Figure 2. Timing Diagram for Standby SignalFigure 3. Timing Diagram for Shutdown Signal Figure 4. Timing Diagram for Shutdown-to-Standby SignalTXDVDIFF0.9VRXD0.5VVCC/2 VCC/2tONTXDtONRXDtOFFTXDtOFFRXDVCC/2 VCC/2Figure 1RSVDIFFtSBRXDLtDRXDL1.1VRXDBUS EXTERNALLYDRIVENVCC x 0.75VCC/2 VCC/2Figure 2SHDNVDIFFtOFFSHDN tONSHDNRXDBUS EXTERNALLYDRIVENVCC/2VCC/2VCC/20.5VFigure 30.75V x VCCRSSHDNVCC/2tSHDNSBFigure 4MAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiverwww.maximintegrated.com Maxim Integrated │ 5Timing Diagrams(VCC = +3.3V, RL = 60Ω, CL = 100pF, TA = +25°C, unless otherwise specified.)SUPPLY CURRENT vs. DATA RATEMAX3051 toc02DATA RATE (kbps)SUPPLY CURRENT (mA)200 400 600 8001316192225100 1000TA = +25°CTA = -40°CTA = +85°CSHUTDOWN SUPPLY CURRENTvs. TEMPERATURE (SHDN = VCC)MAX3051 toc03TEMPERATURE (°C)SHUTDOWN SUPPLY CURRENT (nA)-15 10 35 60204060801001200-40 85DRIVER PROPAGATION DELAYvs. TEMPERATUREMAX3051 toc06TEMPERATURE (°C)DRIVER PROPAGATION DELAY (ns)-15 10 35 6010203040500-40 85RRS = GND, DATA RATE = 100kbpsRECESSIVEDOMINANTSTANDBY SUPPLY CURRENTvs. TEMPERATURE (RS = VCC)MAX3051 toc04TEMPERATURE (°C)STANDBY SUPPLY CURRENT (mA)-15 10 35 608.59.09.510.010.511.08.0-40 85RECEIVER OUTPUT LOWvs. OUTPUT CURRENTMAX3051 toc07OUTPUT CURRENT (mA)VOLTAGE RXD (V)5 10 15 20 25 30 35 400.20.40.60.81.01.21.41.600 45TA = +25°CTA = -40°CTA = -85°CRECEIVER PROPAGATION DELAYvs. TEMPERATUREMAX3051 toc05TEMPERATURE (°C)RECEIVER PROPAGATION DELAY (ns)-15 10 35 6051015202530354045500-40 85RRS = GNDRECESSIVEDOMINANTSLEW RATE vs. RRS AT 100kbpsMAX3051 toc01RRS (kΩ)SLEW RATE (V/µs)20 40 60 80 100 120 140 160 180510152025303500 200MAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiverwww.maximintegrated.com Maxim Integrated │ 6Typical Operating Characteristics(VCC = +3.3V, RL = 60Ω, CL = 100pF, TA = +25°C, unless otherwise specified.)DRIVER PROPAGATION DELAYMAX305 1toc12TXD1V/divCAHN - CANL200ns/divRS = GNDRECEIVER PROPAGATION DELAYMAX3051 toc10RXD1v/divCAHN - CANL200ns/divRS = GNDRECEIVER OUTPUT HIGHvs. OUTPUT CURRENTMAX3051 toc08OUTPUT CURRENT (mA)RECEIVER OUTPUT HIGH (VCC - RXD) (V)1 2 3 4 5 6 70.20.40.60.81.01.21.41.61.800 8LOOPBACK PROPAGATION DELAYvs. RRSMAX3051toc13RRS (kΩ)LOOPBACK PROPAGATION DELAY (ns)20 40 60 80 100 120 140 160 1802004006008001000120000 200DRIVER PROPAGATION DELAYMAX3051 toc11TXD2V/divRRS = 24kΩRRS = 75kΩRRS = 100kΩ200ns/divDIFFERENTIAL VOLTAGEvs. DIFFERENTIAL LOADMAX3051 toc09DIFFERENTIAL LOAD RL (Ω)DIFFERENTIAL VOLTAGE (V)100 2000.51.01.52.02.53.03.500 300TA = -85°CTA = +25°CTA = -40°CMAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiverwww.maximintegrated.com Maxim Integrated │ 7Typical Operating Characteristics (continued)Figure 5. MAX3051 Functional DiagramPIN NAME DESCRIPTION1 TXD Transmit Data Input. TXD is a CMOS/TTL-compatible input from a CAN controller. TXD has an internal75kΩ pullup resistor.2 GND Ground3 VCC Supply Voltage. Bypass VCC to GND with a 0.1μF capacitor.4 RXD Receive Data Output. RXD is a CMOS/TTL-compatible output.5 SHDN Shutdown Input, CMOS/TTL-Compatible. Drive SHDN high to put the MAX3051 in shutdown.SHDN has an internal 75kΩ pulldown resistor to GND.6 CANL CAN Bus Line Low7 CANH CAN Bus Line High8 RSMode-Select Input. Drive RS low or connect to GND for high-speed operation. Connect a resistorbetween RS and GND to control output slope. Drive RS high to put into standby mode (see the ModeSelection section).MAX30510.75VTHERMALSHUTDOWNTRANSMITTERCONTROLMODESELECTIONRECEIVERVCCRSRXDGNDCANLCANHTXDSHUTDOWNSHDNVCCFigure 5MAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiverwww.maximintegrated.com Maxim Integrated │ 8Pin DescriptionDetailed DescriptionThe MAX3051 interfaces between the CAN protocol controller and the physical wires of the bus lines in a CAN.It provides differential transmit capability to the bus anddifferential receive capability to the CAN controller. It isprimarily intended for +3.3V single-supply applicationsthat do not require the stringent fault protection specifiedby the automotive industry (ISO 11898).The MAX3051 features four different modes of operation: high-speed, slope-control, standby, and shutdownmode. High-speed mode allows data rates up to 1Mbps.The slope-control mode can be used to program the slewrate of the transmitter for data rates of up to 500kbps.This reduces the effects of EMI, thus allowing the useof unshielded twisted or parallel cable. In standby mode,the transmitter is shut off and the receiver is pulled high,placing the MAX3051 in low-current mode. In shutdownmode, the transmitter and receiver are switched off.The MAX3051 input common-mode range is from -7V to+12V, exceeding the ISO 11898 specification of -2V to+7V. These features, and the programmable slew-ratelimiting, make the part ideal for nonautomotive, harshenvironments.The transceivers operate from a single +3.3V supply anddraw 35μA of supply current in dominant state and 2μAin recessive state. In standby mode, supply current isreduced to 8μA. In shutdown mode, supply current is lessthan 1μA.CANH and CANL are output short-circuit current limitedand are protected against excessive power dissipation bythermal-shutdown circuitry that places the driver outputsinto a high-impedance state.TransmitterThe transmitter converts a single-ended input (TXD) fromthe CAN controller to differential outputs for the bus lines(CANH, CANL). The truth table for the transmitter andreceiver is given in Table 1.ReceiverThe receiver reads differential inputs from the bus lines(CANH, CANL) and transfers this data as a single-endedoutput (RXD) to the CAN controller. It consists of acomparator that senses the difference VDIFF = (CANH -CANL) with respect to an internal threshold of +0.75V. Ifthis VDIFF is greater than 0.75, a logic-low is present atRXD. If VDIFF is less than 0.75V, a logic-high is present.The receiver always echoes the CAN BUS data.The CANH and CANL common-mode range is -7V to+12V. RXD is logic-high when CANH and CANL areshorted or terminated and undriven.Mode SelectionHigh-Speed ModeConnect RS to ground to set the MAX3051 to highspeed mode. When operating in high-speed mode, theMAX3051 can achieve transmission rates of up to 1Mbps.In high-speed mode, use shielded twisted pair cable toavoid EMI problems.Slope-Control ModeConnect a resistor from RS to ground to select slopecontrol mode (Table 2). In slope-control mode, CANHand CANL slew rates are controlled by the resistor connected to the RS pin. Maximum transmission speeds arecontrolled by RRS and range from 40kbps to 500kbps.Controlling the rise and fall slopes reduces EMI andallows the use of an unshielded twisted pair or a parallelpair of wires as bus lines. The equation for selecting theresistor value is given by:RRS (kΩ) ≈ 12000 / (maximum speed in kbps)See the Slew Rate vs. RRS graph in the Typical OperatingCharacteristics.Standby ModeIf a logic-high is applied to RS, the MAX3051 enters alow-current standby mode. In this mode, the transmitterTable 1. Transmitter and Receiver Truth Table When Not Connected to the BusTXD RS SHDN CANH CANL BUS STATE RXDLow VRS < 0.75 xVCCLow High Low Dominant LowHigh or float VRS < 0.75 xVCCLow 5kΩ to 25kΩ toVCC/25kΩ to 25kΩ toVCC/2 Recessive HighX VRS > 0.75 xVCCLow 5kΩ to 25kΩ toGND5kΩ to 25kΩ toGND Recessive HighX X High Unconnected Unconnected Unconnected HighMAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiverwww.maximintegrated.com Maxim Integrated │ 9is switched off and the receiver is switched to a lowcurrent/low-speed state. If dominant bits are detected,RXD switches to low level. The microcontroller shouldreact to this condition by switching the transceiver backto normal operation.When the MAX3051 enters standby mode, RXDgoes high for 4μs (max) regardless of the BUS state.However, after 4μs, RXD goes low only when the BUS isdominant, otherwise RXD remains high (when the BUSis recessive). For proper measurement of standby-toreceiver active time (tSBRXDL), the BUS should be indominant state (see Figure 2).ShutdownDrive SHDN high to enter shutdown mode. ConnectSHDN to ground or leave unconnected for normaloperation.Thermal ShutdownIf the junction temperature exceeds +160°C, the deviceis switched off. The hysteresis is approximately 25°C,disabling thermal shutdown once the temperature dropsbelow 135°C. In thermal shutdown, CANH and CANL gorecessive and all IC functions are disabled.Applications InformationReduced EMI and ReflectionsIn slope-control mode, the CANH and CANL outputs areslew-rate limited, minimizing EMI and reducing reflectionscaused by improperly terminated cables.In multidrop CAN applications, it is important to maintain adirect point-to-point wiring scheme. A single pair of wiresshould connect each element of the CAN bus, and the twoends of the bus should be terminated with 120Ω resistors(Figure 6). A star configuration should never be used.Any deviation from the point-to-point wiring scheme creates a stub. The high-speed edge of the CAN data ona stub can create reflections back down the bus. Thesereflections can cause data errors by eroding the noisemargin of the system.Although stubs are unavoidable in a multidrop system,care should be taken to keep these stubs as small aspossible, especially in high-speed mode. In slope-controlmode, the requirements are not as rigorous, but stublength should still be minimized.Power Supply and BypassingThe MAX3051 requires no special layout considerationsbeyond common practices. Bypass VCC to GND with a0.1μF ceramic capacitor mounted close to the IC withshort lead lengths and wide trace widths.Table 2. Mode Selection Truth TableCONDITION FORCED AT PIN RS SHDN CANLVRS < 0.3 x VCC High Speed |IRS| < 500μA0.4 x VCC <vrs <="" 0.6="" x="" vcc="" slope="" control="" 10μa="" |irs|="" 200μa="" vrs=""> 0.75 x VCC Standby |IRS| < 10μAMAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiverwww.maximintegrated.com Maxim Integrated │ 10Figure 6. Multiple Receivers Connected to CAN BusPACKAGETYPEPACKAGECODEOUTLINENO.LANDPATTERN NO.8 SO S8+4 21-0041 90-00968 SOT23 K8F+4 21-0078 90-0176MAX3051RL = 120Ω RL = 120Ω TRANSCEIVER 3TRANSCEIVER 1TXDRXDCANHCANLTWISTED PAIRSTUBLENGTHKEEP AS SHORTAS POSSIBLETRANSCEIVER 2Figure 6MAX3051CANCONTROLLERTXDVCCRXDRS GNDCANHCANLVCCTX0RX0GND0.1µF120Ω25kΩ TO 200kΩ120ΩMAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiverwww.maximintegrated.com Maxim Integrated │ 11Typical Operating CircuitChip InformationPROCESS: BiCMOSPackage InformationFor the latest package outline information and land patterns(footprints), go to www.maximintegrated.com/packages. Notethat a “+”, “#”, or “-” in the package code indicates RoHS statusonly. Package drawings may show a different suffix character, butthe drawing pertains to the package regardless of RoHS status.REVISIONNUMBERREVISIONDATE DESCRIPTION PAGESCHANGED2 10/12 Added lead-free part information to the data sheet 1–133 2/15 Updated front page content 1Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licensesare implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.MAX3051 +3.3V, 1Mbps, Low-Supply-CurrentCAN Transceiver© 2015 Maxim Integrated Products, Inc. │ 12Revision HistoryFor pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com

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