MAX491MJD资料

19-0122; Rev 8; 10/03

Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers

General Description

__Next Generation Device Features

The MAX481, MAX483, MAX485, MAX487–MAX491, andMAX1487 are low-power transceivers for RS-485 and RS-♦For Fault-Tolerant Applications

422 communication. Each part contains one driver and oneMAX3430: ±80V Fault-Protected, Fail-Safe, 1/4receiver. The MAX483, MAX487, MAX488, and MAX4Unit Load, +3.3V, RS-485 Transceiver

feature reduced slew-rate drivers that minimize EMI andMAX3440E–MAX3444E: ±15kV ESD-Protected,reduce reflections caused by improperly terminated cables,±60V Fault-Protected, 10Mbps, Fail-Safe, thus allowing error-free data transmission up to 250kbps.The driver slew rates of the MAX481, MAX485, MAX490,RS-485/J1708 Transceivers

MAX491, and MAX1487 are not limited, allowing them to♦For Space-Constrained Applications

transmit up to 2.5Mbps.

MAX3460–MAX34: +5V, Fail-Safe, 20Mbps,These transceivers draw between 120µA and 500µA ofProfibus RS-485/RS-422 Transceivers

supply current when unloaded or fully loaded with disabledMAX3362: +3.3V, High-Speed, RS-485/RS-422drivers. Additionally, the MAX481, MAX483, and MAX487Transceiver in a SOT23 Package

have a low-current shutdown mode in which they consumeMAX3280E–MAX3284E: ±15kV ESD-Protected,only 0.1µA. All parts operate from a single 5V supply.

52Mbps, +3V to +5.5V, SOT23, RS-485/RS-422,Drivers are short-circuit current limited and are protectedTrue Fail-Safe Receivers

against excessive power dissipation by thermal shutdowncircuitry that places the driver outputs into a high-imped-MAX3293/MAX3294/MAX3295: 20Mbps, +3.3V,ance state. The receiver input has a fail-safe feature thatSOT23, RS-855/RS-422 Transmittersguarantees a logic-high output if the input is open circuit.♦For Multiple Transceiver Applications

The MAX487 and MAX1487 feature quarter-unit-loadMAX3030E–MAX3033E: ±15kV ESD-Protected,receiver input impedance, allowing up to 128 MAX487/+3.3V, Quad RS-422 TransmittersMAX1487 transceivers on the bus. Full-duplex communi-♦For Fail-Safe Applications

cations are obtained using the MAX488–MAX491, whilethe MAX481, MAX483, MAX485, MAX487, and MAX1487MAX3080–MAX30: Fail-Safe, High-Speedare designed for half-duplex applications.

(10Mbps), Slew-Rate-Limited RS-485/RS-422Transceivers

________________________Applications

♦For Low-Voltage Applications

Low-Power RS-485 TransceiversMAX3483E/MAX3485E/MAX3486E/MAX3488E/Low-Power RS-422 TransceiversMAX3490E/MAX3491E: +3.3V Powered, ±15kVLevel Translators

ESD-Protected, 12Mbps, Slew-Rate-Limited,True RS-485/RS-422 Transceivers

Transceivers for EMI-Sensitive ApplicationsIndustrial-Control Local Area Networks

Ordering Information appears at end of data sheet.

______________________________________________________________Selection Table

PARTHALF/FULLDATA RATESLEW-RATELOW-POWERRECEIVER/QUIESCENTNUMBER OFNUMBERDUPLEX(Mbps)LIMITEDSHUTDOWNDRIVERCURRENTTRANSMITTERSPINENABLE(µA)ON BUSCOUNTMAX481Half2.5NoYesYes300328MAX483Half0.25YesYesYes120328MAX485Half2.5NoNoYes300328MAX487Half0.25YesYesYes1201288MAX488Full0.25YesNoNo120328MAX4Full0.25YesNoYes1203214MAX490Full2.5NoNoNo300328MAX491Full2.5NoNoYes3003214MAX1487Half2.5NoNoYes2301288________________________________________________________________Maxim Integrated Products1For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-42, or visit Maxim’s website at www.maxim-ic.com.

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487元器件交易网www.cecb2b.com

Low-Power, Slew-Rate-LimitedRS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487ABSOLUTE MAXIMUM RATINGS

Supply Voltage (VCC).............................................................12VControl Input Voltage (RE, DE)...................-0.5V to (VCC+ 0.5V)Driver Input Voltage (DI).............................-0.5V to (VCC+ 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 (VCC+0.5V)Continuous Power Dissipation (TA= +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)...............667mW8-Pin µMAX (derate 4.1mW/°C above +70°C)..............830mW8-Pin CERDIP (derate 8.00mW/°C above +70°C).........0mW14-Pin CERDIP (derate 9.09mW/°C above +70°C).......727mWOperating Temperature Ranges

MAX4_ _C_ _/MAX1487C_ A...............................0°C to +70°CMAX4__E_ _/MAX1487E_ A.............................-40°C to +85°CMAX4__MJ_/MAX1487MJA...........................-55°C to +125°CStorage Temperature Range.............................-65°C to +160°CLead Temperature (soldering, 10sec).............................+300°C

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.

DC ELECTRICAL CHARACTERISTICS

(VCC= 5V ±5%, TA= TMINto TMAX, unless otherwise noted.) (Notes 1, 2)

PARAMETER

Differential Driver Output (no load)Differential Driver Output(with load)

Change in Magnitude of DriverDifferential Output Voltage forComplementary Output StatesDriver Common-Mode OutputVoltage

Change in Magnitude of DriverCommon-Mode Output Voltagefor Complementary Output StatesInput High VoltageInput Low VoltageInput Current

SYMBOLVOD1VOD2∆VODVOC∆VODVIHVILIIN1

R = 50Ω(RS-422)

R = 27Ω(RS-485), Figure 4R = 27Ωor 50Ω, Figure 4R = 27Ωor 50Ω, Figure 4R = 27Ωor 50Ω, Figure 4DE, DI, REDE, DI, REDE, DI, REDE = 0V;

VCC= 0V or 5.25V,all devices exceptMAX487/MAX1487

MAX487/MAX1487,

DE = 0V, VCC= 0V or 5.25V

Receiver Differential ThresholdVoltage

Receiver Input HysteresisReceiver Output High VoltageReceiver Output Low VoltageThree-State (high impedance)Output Current at Receiver

VTH∆VTHVOHVOLIOZR

-7V ≤VCM≤12VVCM= 0V

IO= -4mA, VID= 200mVIO = 4mA, VID= -200mV0.4V ≤VO≤2.4V

-7V ≤VCM≤12V, all devices exceptMAX487/MAX1487

-7V ≤VCM ≤12V, MAX487/MAX1487

12483.5

0.4±1

VIN= 12VVIN= -7VVIN= 12VVIN= -7V

-0.2

70

2.0

0.8±21.0

mA

-0.80.25-0.20.2

mAVmVVVµAkΩkΩ

21.5

50.230.2

CONDITIONS

MIN

TYP

MAX5

UNITSVVVVVVVµA

Input Current(A, B)

IIN2

Receiver Input ResistanceRIN

2_______________________________________________________________________________________

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Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers

DC ELECTRICAL CHARACTERISTICS (continued)

(VCC= 5V ±5%, TA= TMINto TMAX, unless otherwise noted.) (Notes 1, 2)

PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSMAX488/MAX4,DE, DI, RE= 0V or VCC120250MAX490/MAX491,DE, DI, RE= 0V or VCC300500No-Load Supply CurrentMAX481/MAX485,DE = VCC500900(Note 3)ICCRE= 0V or VCCDE = 0V300500µAMAX1487,DE = VCC300500RE= 0V or VCCDE = 0V230400MAX483/MAX487,DE = 5VMAX483350650RE= 0V or VCCMAX487250400DE = 0V120250Supply Current in Shutdown ISHDNMAX481/483/487, DE = 0V, RE= VCC0.110µADriver Short-Circuit Current,VO= HighIOSD1-7V ≤VO≤12V (Note 4)35250mADriver Short-Circuit Current,VO= LowIOSD2-7V ≤VO≤12V (Note 4)35250mAReceiver Short-Circuit CurrentIOSR0V ≤VO≤VCC795mASWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487

(VCC= 5V ±5%, TA= TMINto TMAX, unless otherwise noted.) (Notes 1, 2)

PARAMETER

SYMBOLCONDITIONSMINTYPMAXUNITSDriver Input to OutputtPLHFigures 6 and 8, RDIFF= Ω,

103060tPHL

CL1= CL2= 100pF103060nsDriver Output Skew to OutputtSKEWFigures 6 and 8, RDIFF= Ω, CL1= CL2= 100pF510nsFigures 6 and 8,

MAX481, MAX485, MAX1487310Driver Rise or Fall TimetR, tFRDIFF= Ω,MAX490C/E, MAX491C/E51525nsCL1= CL2= 100pFMAX490M, MAX491M

3

10Driver Enable to Output HightZHFigures 7 and 9, CL= 100pF, S2 closed4070nsDriver Enable to Output LowtZLFigures 7 and 9, CL= 100pF, S1 closed4070nsDriver Disable Time from LowtLZFigures 7 and 9, CL= 15pF, S1 closed4070nsDriver Disable Time from HightHZFigures 7 and 9, CL= 15pF, S2 closed

4070nsFigures 6 and 10,MAX481, MAX485, MAX1487

2090200Receiver Input to Output

tPLH, tPHLRDIFF= Ω,MAX490C/E, MAX491C/E

2090150ns

CL1= CL2= 100pFMAX490M, MAX491M20

90200

|tPLH- tPHL|Differential

Receiver Skew

tSKDFigures 6 and 10, RDIFF= Ω,CL1= CL2= 100pF

13nsReceiver Enable to Output LowtZLFigures 5 and 11, CRL= 15pF, S1 closed2050nsReceiver Enable to Output HightZHFigures 5 and 11, CRL= 15pF, S2 closed2050nsReceiver Disable Time from LowtLZFigures 5 and 11, CRL= 15pF, S1 closed2050nsReceiver Disable Time from HightHZFigures 5 and 11, CRL= 15pF, S2 closed

2050nsMaximum Data RatefMAX2.5MbpsTime to Shutdown

tSHDN

MAX481 (Note 5)

50200

600ns

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MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487元器件交易网www.cecb2b.com

Low-Power, Slew-Rate-LimitedRS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487 (continued)

(VCC= 5V ±5%, TA= TMINto TMAX, unless otherwise noted.) (Notes 1, 2)

PARAMETER

SYMBOL

CONDITIONS

Figures 7 and 9, CL= 100pF, S2 closedFigures 7 and 9, CL= 100pF, S1 closedFigures 5 and 11, CL= 15pF, S2 closed,A - B = 2V

Figures 5 and 11, CL= 15pF, S1 closed,B - A = 2V

MIN

TYP4040300300

MAX10010010001000

UNITSnsnsnsns

Driver Enable from Shutdown to

tZH(SHDN)

Output High (MAX481)

Driver Enable from Shutdown to

tZL(SHDN)

Output Low (MAX481)

Receiver Enable from Shutdown

tZH(SHDN)

to Output High (MAX481)

Receiver Enable from Shutdown

tZL(SHDN)

to Output Low (MAX481)

SWITCHING CHARACTERISTICS—MAX483, MAX487/MAX488/MAX4

(VCC= 5V ±5%, TA= TMINto TMAX, unless otherwise noted.) (Notes 1, 2)

PARAMETER

Driver Input to OutputDriver Output Skew to OutputDriver Rise or Fall TimeDriver Enable to Output HighDriver Enable to Output LowDriver Disable Time from LowDriver Disable Time from HighReceiver Input to Output

SYMBOLtPLHtPHLtSKEWtR, tFtZHtZLtLZtHZtPLHtPHLtSKDtZLtZHtLZtHZfMAXtSHDNtZH(SHDN)tZL(SHDN)tZH(SHDN)tZL(SHDN)

CONDITIONS

Figures 6 and 8, RDIFF= Ω,CL1= CL2= 100pF

Figures 6 and 8, RDIFF= Ω,CL1= CL2= 100pF

Figures 6 and 8, RDIFF= Ω,CL1= CL2= 100pF

Figures 7 and 9, CL= 100pF, S2 closedFigures 7 and 9, CL= 100pF, S1 closedFigures 7 and 9, CL= 15pF, S1 closedFigures 7 and 9, CL= 15pF, S2 closedFigures 6 and 10, RDIFF= Ω,CL1= CL2= 100pF

Figures 6 and 10, RDIFF= Ω,CL1= CL2= 100pF

Figures 5 and 11, CRL= 15pF, S1 closedFigures 5 and 11, CRL= 15pF, S2 closedFigures 5 and 11, CRL= 15pF, S1 closedFigures 5 and 11, CRL= 15pF, S2 closedtPLH, tPHL< 50% of data periodMAX483/MAX487 (Note 5) MAX483/MAX487, Figures 7 and 9,CL= 100pF, S2 closed

MAX483/MAX487, Figures 7 and 9,CL= 100pF, S1 closed

MAX483/MAX487, Figures 5 and 11,CL= 15pF, S2 closed

MAX483/MAX487, Figures 5 and 11,CL= 15pF, S1 closed

25050

200

6002000200025002500

250250250300300250250

10020202020

50505050

MIN250250

TYP800800100

MAX200020008002000200020003000300020002000

UNITSnsnsnsnsnsnsnsnsnsnsnsnsnskbpsnsnsnsnsns

ItPLH- tPHLIDifferential

Receiver Skew

Receiver Enable to Output LowReceiver Enable to Output HighReceiver Disable Time from LowReceiver Disable Time from HighMaximum Data RateTime to Shutdown

Driver Enable from Shutdown toOutput High

Driver Enable from Shutdown toOutput Low

Receiver Enable from Shutdownto Output High

Receiver Enable from Shutdownto Output Low

4_______________________________________________________________________________________

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Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers

NOTES FOR ELECTRICAL/SWITCHING CHARACTERISTICS

Note 1:All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device

ground unless otherwise specified.

Note 2:All typical specifications are given for VCC= 5V and TA= +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 bringingREhigh and DE low. If the inputs are in this state for less

than 50ns, the parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 600ns, the parts areguaranteed to have entered shutdown. See Low-Power Shutdown Modesection.

__________________________________________Typical Operating Characteristics

(VCC= 5V, TA = +25°C, unless otherwise noted.)

OUTPUT CURRENT vs.

OUTPUT CURRENT vs.

RECEIVER OUTPUT HIGH VOLTAGE vs.

RECEIVER OUTPUT LOW VOLTAGE

RECEIVER OUTPUT HIGH VOLTAGE

TEMPERATURE

451-20200-4.8

30--1811488X-184440AXXMAAM4.6IRO = 8mAM)))-16VA35A( 4.4mmE((G -14T30TANNT4.2EE-12LRROR25RV 4.0UU-10HCCG IT20TH3.8UU-8 PPTT15TUUUP3.6OT10O-6-4UO3.45-23.200

3.0

0

0.5

1.0

1.5

2.0

2.51.52.02.53.03..04.55.0-50-250255075100125

OUTPUT LOW VOLTAGE (V)OUTPUT HIGH VOLTAGE (V)TEMPERATURE (°C)

RECEIVER OUTPUT LOW VOLTAGE vs.

DRIVER OUTPUT CURRENT vs.DRIVER DIFFERENTIAL OUTPUT VOLTAGE

TEMPERATURE

DIFFERENTIAL OUTPUT VOLTAGE

vs. TEMPERATURE

0.9409052.4

6-00--18110.8I488X4RO = 8mA80X)AAMMV(2.3R = Ω4XAM )EVG()A 0.7EA70T2.2GmLA( OT0.6TV2.1 LN60OETVRUP2.0 0.5WR50UTOCUL0.4 O T40TL1.9UUPAIP0.3T30TTN1.8UUEO0.2O20RE1.7FF0.110ID1.600

1.5

-50

-25

0

25

50

75

10012500.51.01.52.02.53.03..04.5-50

-25

0

25

50

75

100

125

TEMPERATURE (°C)DIFFERENTIAL OUTPUT VOLTAGE (V)

TEMPERATURE (°C)

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MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487元器件交易网www.cecb2b.com

Low-Power, Slew-Rate-LimitedRS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487____________________________Typical Operating Characteristics (continued)

(VCC= 5V, TA = +25°C, unless otherwise noted.)

OUTPUT CURRENT vs.DRIVER OUTPUT LOW VOLTAGE

MAX481-07OUTPUT CURRENT vs.DRIVER OUTPUT HIGH VOLTAGE

MAX481-08MAX481/MAX485/MAX490/MAX491SUPPLY CURRENT vs. TEMPERATURE

MAX481/MAX485; DE = VCC, RE = XMAX481-11140120OUTPUT CURRENT (mA)1008060402000

2

4

6

8

10

-120-100OUTPUT CURRENT (mA)-80-60-40-200

600500SUPPLY CURRENT (µA)4003002001000

MAX481; DE = 0, RE = VCCMAX485; DE = 0, RE = X,MAX481; DE = RE = 0MAX490/MAX491; DE = RE = X12-7-6-5-4-3-2-1012345-50-250255075100125

OUTPUT LOW VOLTAGE (V)OUTPUT HIGH VOLTAGE (V)TEMPERATURE (°C)

MAX483/MAX487–MAX4

SUPPLY CURRENT vs. TEMPERATURE

MAX481-12MAX1487

SUPPLY CURRENT vs. TEMPERATURE

MAX481-13600500SUPPLY CURRENT (µA)400300

MAX487; DE = VCC, RE = XMAX483; DE = VCC, RE = X600500SUPPLY CURRENT (µA)400300200100

MAX1487; DE = VCC, RE = X200100

MAX483/MAX487; DE = RE = 0,MAX488/MAX4; DE = RE = XMAX1487; DE = 0V, RE = XMAX483/MAX487; DE = 0, RE = VCC0-50

-25

0

25

50

75

100

125

TEMPERATURE (°C)

0

-60-40-20

02040

6080100120140

TEMPERATURE (°C)

6_______________________________________________________________________________________

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Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers

______________________________________________________________Pin Description

PINMAX481/MAX483/MAX485/MAX487/MAX488/MAX4/NAMENAMEFUNCTIONFUNCTIONMAX1487MAX490MAX491DIP/SOµMAXDIP/SOµMAXDIP/SO13242ROReceiver Output: If A > B by 200mV, RO will be high;If A < B by 200mV, RO will be low.24——3REReceiver Output Enable. RO is enabled whenREis low; RO ishigh impedance whenREis high.Driver Output Enable. The driver outputs, Y and Z, are enabledby bringing DE high. They are high impedance when DE is low. If35——4DEthe driver outputs are enabled, the parts function as line drivers.While they are high impedance, theyfunction as line receivers ifREis low.46355DIDriver Input. A low on DI forces output Y low and output Z high.Similarly, a high on DI forces output Y high and output Z low.57466, 7GNDGround——579YNoninverting Driver Output——6810ZInverting Driver Output68———ANoninverting Receiver Input and Noninverting Driver Output——8212ANoninverting Receiver Input71———BInverting Receiver Input and Inverting Driver Output——7111BInverting Receiver Input821314VCCPositive Supply: 4.75V ≤VCC≤5.25V————1, 8, 13N.C.No Connect—not internally connectedTOP VIEWRO1R8VCCMAX481RE27BMAX483MAX485DE36AMAX487DEDI4MAX1487D5GND RO1R8VCCDDIRE27BBDIP/SORtRtDE36AAB18ADI4D5GND RROVCC2MAX4817GND RO3MAX483REMAX4856DIRE4MAX487MAX14875DENOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.µMAX TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.Figure 1. MAX481/MAX483/MAX485/MAX487/MAX1487 Pin Configuration and Typical Operating Circuit

_______________________________________________________________________________________

7

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487元器件交易网www.cecb2b.com

Low-Power, Slew-Rate-LimitedRS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487TOP VIEWVCC1RO2DI3GND4DR8765ABZY DI35YVCC1VCCMAX488MAX490RtD6ZRRODIP/SO8ABAVCCRO12348ZYGNDDI4GNDNOTE: TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.GNDRO2R7BRtDDIMAX488MAX490765µMAXFigure 2. MAX488/MAX490 Pin Configuration and Typical Operating Circuit

TOP VIEWDE4VCC149YMAX4MAX491RtZ12ARt11BVCCREN.C.ROREDEDIGNDGND1234567DR14VCC13N.C.12A11B10Z98YN.C.NC1, 8, 133RO2DI5D10RRORDDIDIP/SO6, 7REGNDGNDDEFigure 3. MAX4/MAX491 Pin Configuration and Typical Operating Circuit

__________Applications Information

The MAX481/MAX483/MAX485/MAX487–MAX491 andMAX1487 are low-power transceivers for RS-485 and RS-422 communications. The MAX481, MAX485, MAX490,MAX491, and MAX1487 can transmit and receive at datarates up to 2.5Mbps, while the MAX483, MAX487,MAX488, and MAX4 are specified for data rates up to250kbps. 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 theMAX481, MAX483, MAX485, MAX487, MAX4,MAX491, and MAX1487. When disabled, the driver andreceiver outputs are high impedance.

8

MAX487/MAX1487:

128 Transceivers on the Bus

The 48kΩ, 1/4-unit-load receiver input impedance of theMAX487 and MAX1487 allows up to 128 transceiverson a bus, compared to the 1-unit load (12kΩinputimpedance) of standard RS-485 drivers (32 trans-ceivers maximum). Any combination of MAX487/MAX1487 and other RS-485 transceivers with a total of32 unit loads or less can be put on the bus. TheMAX481/MAX483/MAX485 and MAX488–MAX491 havestandard 12kΩReceiver Input impedance.

_______________________________________________________________________________________

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Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers

_________________________________________________________________Test Circuits

YRRECEIVERTEST POINT1kΩOUTPUTVVS1CCODCRL15pF1kΩRVOCZS2Figure 4. Driver DC Test LoadFigure 5. Receiver Timing Test Load

3VVDECCCL1AOUTPUT500ΩS1DIYRVDIFFROUNDER TESTIDZBCLRES2CL2Figure 6. Driver/Receiver Timing Test CircuitFigure 7. Driver Timing Test Load

MAX483/MAX487/MAX488/MAX4:

monics with large amplitudes are evident. Figure 13Reduced EMI and Reflections

shows the same information displayed for a MAX483,The MAX483 and MAX487–MAX4 are slew-rate limit-MAX487, MAX488, or MAX4 transmitting under theed, minimizing EMI and reducing reflections caused bysame conditions. Figure 13’s high-frequency harmonicsimproperly terminated cables. Figure 12 shows the dri-have much lower amplitudes, and the potential for EMIver output waveform and its Fourier analysis of ais significantly reduced.

150kHz signal transmitted by a MAX481, MAX485,MAX490, MAX491, or MAX1487. High-frequency har-

_______________________________________________________________________________________9

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Low-Power, Slew-Rate-LimitedRS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487_______________________________________________________Switching Waveforms

3VDI0VZYVO0V-VOVO1/2 VOVDIFF10%tRtSKEW = | tPLH - tPHL |1.5VtPLHtPHL1.5V1/2 VO3VDE0VtZL(SHDN), tZLtLZVOL +0.5V1.5V1.5VY, ZVOLVDIFF = V (Y) - V (Z)90%90%tF10%Y, Z0V2.3VOUTPUT NORMALLY LOWOUTPUT NORMALLY HIGH2.3VtZH(SHDN), tZHtHZVOH -0.5VFigure 8. Driver Propagation Delays

Figure 9. Driver Enable and Disable Times (except MAX488 andMAX490)

3VRE0VROVOHVOLVID-VID0V1.5VtPHLINPUTOUTPUTtPLH0VRO0VtZH(SHDN), tZHtHZ1.5V1.5VVCCROtZL(SHDN), tZLtLZVOL + 0.5V1.5V1.5V1.5VOUTPUT NORMALLY LOWOUTPUT NORMALLY HIGHA-BVOH - 0.5VFigure 10. Receiver Propagation Delays

Figure 11. Receiver Enable and Disable Times (except MAX488and MAX490)

_________________Function Tables (MAX481/MAX483/MAX485/MAX487/MAX1487)

Table 1. Transmitting

INPUTSREXX01DE1100DI10XXZ01High-ZHigh-Z*OUTPUTSY10High-ZHigh-Z*RE0001Table 2. Receiving

INPUTSDE0000A-B> +0.2V< -0.2VInputs openXOUTPUTRO101High-Z*X = Don't careHigh-Z = High impedance* Shutdown mode for MAX481/MAX483/MAX487X = Don't careHigh-Z = High impedance* Shutdown mode for MAX481/MAX483/MAX48710______________________________________________________________________________________元器件交易网www.cecb2b.com

Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers

10dB/div

10dB/div

0Hz

5MHz

0Hz

5MHz

500kHz/div

500kHz/div

Figure 12. Driver Output Waveform and FFT Plot of MAX481/Figure 13. Driver Output Waveform and FFT Plot of MAX483/MAX485/MAX490/MAX491/MAX1487 Transmitting a 150kHzMAX487–MAX4 Transmitting a 150kHz Signal

Signal

Low-Power Shutdown ModeDriver Output Protection

(MAX481/MAX483/MAX487)

Excessive output current and power dissipation causedA low-power shutdown mode is initiated by bringingby faults or by bus contention are prevented by twoboth REhigh and DE low. The devices will not shutmechanisms. A foldback current limit on the outputdown unless both the driver and receiver are disabled.stage provides immediate protection against short cir-In shutdown, the devices typically draw only 0.1µA ofcuits over the whole common-mode voltage range (seesupply current.

Typical Operating Characteristics). In addition, a ther-REand DE may be driven simultaneously; the parts aremal shutdown circuit forces the driver outputs into aguaranteed not to enter shutdown if REis high and DEhigh-impedance state if the die temperature risesis low for less than 50ns. If the inputs are in this stateexcessively.

for at least 600ns, the parts are guaranteed to entershutdown.

Propagation Delay

Many digital encoding schemes depend on the differ-For the MAX481, MAX483, and MAX487, the tZHandence between the driver and receiver propagationtZLenable times assume the part was not in the low-delay times. Typical propagation delays are shown inpower shutdown state (the MAX485/MAX488–MAX491Figures 15–18 using Figure 14’s test circuit.

and MAX1487 can not be shut down). The tand tZH(SHDN)ZL(SHDN)enable times assume the parts were shutThe difference in receiver delay times, | tPLH- tdown (see Electrical Characteristics).

typically under 13ns for the MAX481, MAX485,PHL|, isMAX490, MAX491, and MAX1487 and is typically lessIt takes the drivers and receivers longer to becomethan 100ns for the MAX483 and MAX487–MAX4.enabled from the low-power shutdown state(tThe driver skew times are typically 5ns (10ns max) for(tZH(SHDN), tZL(SHDN)) than from the operating modeZH, tZL). (The parts are in operating mode if the –R—E–,the MAX481, MAX485, MAX490, MAX491, andDE inputs equal a logical 0,1 or 1,1 or 0, 0.)

MAX1487, and are typically 100ns (800ns max) for theMAX483 and MAX487–MAX4.

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Low-Power, Slew-Rate-LimitedRS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487100pFZTTL INtR, tF < 6nsDYR = ΩABRRECEIVEROUT100pFFigure 14. Receiver Propagation Delay Test Circuit

A500mV/divVCC = 5VTA = +25°CB500mV/divVCC = 5VTA = +25°CBROA2V/div2V/divRO20ns/div20ns/divFigure 15. MAX481/MAX485/MAX490/MAX491/MAX1487Receiver tPHL

Figure 16. MAX481/MAX485/MAX490/MAX491/MAX1487Receiver tPLH

A500mV/divVCC = 5VTA = +25°CB500mV/divVCC = 5VTA = +25°CBRO2V/divA2V/divRO400ns/div400ns/divFigure 17. MAX483, MAX487–MAX4 Receiver tPHLFigure 18. MAX483, MAX487–MAX4 Receiver tPLH

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Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers

Line Length vs. Data Rate

Figures 21 and 22 show typical network applicationsThe RS-485/RS-422 standard covers line lengths up tocircuits. These parts can also be used as line4000 feet. For line lengths greater than 4000 feet, seerepeaters, with cable lengths longer than 4000 feet, asFigure 23.

shown in Figure 23.

Figures 19 and 20 show the system differential voltageTo minimize reflections, the line should be terminated atfor the parts driving 4000 feet of 26AWG twisted-pairboth ends in its characteristic impedance, and stubwire at 110kHz into 120Ωloads.

lengths off the main line should be kept as short as possi-Typical Applications

ble. The slew-rate-limited MAX483 and MAX487–MAX4The MAX481, MAX483, MAX485, MAX487–MAX491, andare more tolerant of imperfect termination.

MAX1487 transceivers are designed for bidirectional datacommunications on multipoint bus transmission lines.

DI

5VDI5V0V

0V1V

1VVY-VZ

0VVY-VZ0V-1V

-1VRO

5VRO5V0V

0V2µs/div

2µs/divFigure 19. MAX481/MAX485/MAX490/MAX491/MAX1487 SystemFigure 20. MAX483, MAX487–MAX4 System DifferentialDifferential Voltage at 110kHz Driving 4000ft of CableVoltage at 110kHz Driving 4000ft of Cable

120Ω120ΩDIBBDEDDDIDEABABAARORRRORERERRMAX481DDMAX483MAX485MAX487MAX1487DIDEROREDIDEROREFigure 21. MAX481/MAX483/MAX485/MAX487/MAX1487 Typical Half-Duplex RS-485 Network

______________________________________________________________________________________13

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Low-Power, Slew-Rate-LimitedRS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487AROREDEZDIY120Ω120ΩZDEB120Ω120ΩYZBAYZBAARERORBDDIDYRRDDRMAX4MAX491DERERODIDERERODINOTE: RE AND DE ON MAX4/MAX491 ONLY.Figure 22. MAX488–MAX491 Full-Duplex RS-485 Network

Isolated RS-485

MAX488–MAX491AROREDEDIFor isolated RS-485 applications, see the MAX253 andMAX1480 data sheets.

RB120ΩDATA INZD120ΩYDATA OUTNOTE: RE AND DE ON MAX4/MAX491 ONLY.Figure 23. Line Repeater for MAX488–MAX491

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Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers

_______________Ordering Information

__Ordering Information (continued)

PARTTEMP. RANGEPIN-PACKAGEPARTTEMP. RANGEPIN-PACKAGEMAX481CPA0°C to +70°C8 Plastic DIPMAX490CPA0°C to +70°C8 Plastic DIPMAX481CSA0°C to +70°C8 SOMAX490CSA0°C to +70°C8 SOMAX481CUA0°C to +70°C8 µMAXMAX490CUA0°C to +70°C8 µMAXMAX481C/D0°C to +70°CDice*MAX490C/D0°C to +70°CDice*MAX481EPA-40°C to +85°C8 Plastic DIPMAX490EPA-40°C to +85°C8 Plastic DIPMAX481ESA-40°C to +85°C8 SOMAX490ESA-40°C to +85°C8 SOMAX481MJA-55°C to +125°C8 CERDIPMAX490MJA-55°C to +125°C8 CERDIPMAX483CPA0°C to +70°C8 Plastic DIPMAX491CPD0°C to +70°C14 Plastic DIPMAX483CSA0°C to +70°C8 SOMAX491CSD0°C to +70°C14 SOMAX483CUA0°C to +70°C8 µMAXMAX491C/D0°C to +70°CDice*MAX483C/D0°C to +70°CDice*MAX491EPD-40°C to +85°C14 Plastic DIPMAX483EPA-40°C to +85°C8 Plastic DIPMAX491ESD-40°C to +85°C14 SOMAX483ESA-40°C to +85°C8 SOMAX491MJD-55°C to +125°C14 CERDIPMAX483MJA-55°C to +125°C8 CERDIPMAX1487CPA0°C to +70°C8 Plastic DIPMAX485CPA0°C to +70°C8 Plastic DIPMAX1487CSA0°C to +70°C8 SOMAX485CSA0°C to +70°C8 SOMAX1487CUA0°C to +70°C8 µMAXMAX485CUA0°C to +70°C8 µMAXMAX1487C/D0°C to +70°CDice*MAX485C/D0°C to +70°CDice*MAX1487EPA-40°C to +85°C8 Plastic DIPMAX485EPA-40°C to +85°C8 Plastic DIPMAX1487ESA-40°C to +85°C8 SOMAX485ESA-40°C to +85°C8 SOMAX1487MJA-55°C to +125°C8 CERDIPMAX485MJA-55°C to +125°C8 CERDIP* Contact factory for dice specifications.

MAX487CPA0°C to +70°C8 Plastic DIPMAX487CSA0°C to +70°C8 SOMAX487CUA0°C to +70°C8 µMAXMAX487C/D0°C to +70°CDice*_________________Chip Topographies

MAX487EPA-40°C to +85°C8 Plastic DIPMAX487ESA-40°C to +85°C8 SOMAX481/MAX483/MAX485/MAX487/MAX1487

MAX487MJA-55°C to +125°C8 CERDIPVMAX488CPA0°C to +70°C8 Plastic DIPCCMAX488CSA0°C to +70°C8 SO RON.C.MAX488CUA0°C to +70°C8 µMAXMAX488C/D0°C to +70°CDice* REN.C.MAX488EPA-40°C to +85°C8 Plastic DIPB0.0\"MAX488ESA-40°C to +85°C8 SO DE(1.372mm)MAX488MJA-55°C to +125°C8 CERDIP DIAMAX4CPD0°C to +70°C14 Plastic DIPMAX4CSD0°C to +70°C14 SOGNDMAX4C/D0°C to +70°CDice*0.080\"MAX4EPD-40°C to +85°C14 Plastic DIP(2.032mm)MAX4ESD-40°C to +85°C14 SOMAX4MJD-55°C to +125°C14 CERDIP______________________________________________________________________________________15

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487元器件交易网www.cecb2b.com

Low-Power, Slew-Rate-LimitedRS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487_____________________________________________Chip Topographies (continued)

MAX488/MAX490

VCC RO N.C. N.C. DIGND0.080\"(2.032mm)ABZY0.0\"(1.372mm) RO RE DE DIGND0.080\"(2.032mm)MAX4/MAX491

VCCABZY0.0\"(1.372mm)TRANSISTOR COUNT: 248SUBSTRATE CONNECTED TO GND

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Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline informationgo to www.maxim-ic.com/packages.)

SPE. INCHESMILLIMETERSNCIDIMMINMAXMINMAXOSA0.0530.0691.351.75NA10.0040.0100.100.25B0.0140.0190.350.49C0.0070.0100.190.25e0.050 BSC1.27 BSCE0.1500.1573.804.00EHH0.2280.2445.806.20L0.0160.0500.401.27VARIATIONS:1INCHESMILLIMETERSTOP VIEWDIMMINMAXMINMAXNMS012D0.10.1974.805.008AAD0.3370.3448.558.7514ABD0.3860.3949.8010.0016ACDACeBA10∞-8∞LFRONT VIEWSIDE VIEWPROPRIETARY INFORMATIONTITLE:PACKAGE OUTLINE, .150\" SOICAPPROVALDOCUMENT CONTROL NO.REV.21-0041B11______________________________________________________________________________________17

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487元器件交易网www.cecb2b.com

Low-Power, Slew-Rate-LimitedRS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Package Information (continued)

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline informationgo to www.maxim-ic.com/packages.)

8LUMAXD.EPS84X S8INCHESDIMAA1A2bcDeEHMIN-0.0020.030MAX0.0430.0060.037MILLIMETERSMAXMIN-0.050.751.100.150.95ÿ0.50±0.10.6±0.1EH10.6±0.11DLαSBOTTOM VIEW0.0140.0100.0070.0050.1200.1160.0256 BSC0.1200.1160.1980.1880.0260.0160∞6∞0.0207 BSC0.250.360.130.182.953.050.65 BSC2.953.0.785.030.410.660∞6∞0.5250 BSCTOP VIEWA2A1AcebLαSIDE VIEWFRONT VIEWPROPRIETARY INFORMATIONTITLE:PACKAGE OUTLINE, 8L uMAX/uSOPAPPROVALDOCUMENT CONTROL NO.REV.21-0036J1118______________________________________________________________________________________

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Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers

7Package Information (continued)

8(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information4go to www.maxim-ic.com/packages.)

1XSPE.ANPIDPM/194XAM–784XAM/584XAM/384XAM/184XAMMaxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses areimplied. 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 Products

Printed USA

is a registered trademark of Maxim Integrated Products.

MAX481/MAX483/MAX485/MAX487–MAX491