Datasheet

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General Description

The 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 MAX489

feature 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 MAX487

have 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 MAX1487

are designed for half-duplex applications.

________________________Applications

Low-Power RS-485 Transceivers

Low-Power RS-422 Transceivers

Level Translators

Transceivers for EMI-Sensitive Applications

Industrial-Control Local Area Networks

__Next Generation Device Features

o For Fault-Tolerant Applications

MAX3430: ±80V Fault-Protected, Fail-Safe, 1/4

Unit Load, +3.3V, RS-485 Transceiver

MAX3440E–MAX3444E: ±15kV ESD-Protected,

±60V Fault-Protected, 10Mbps, Fail-Safe,

RS-485/J1708 Transceivers

o For Space-Constrained Applications

MAX3460–MAX3464: +5V, Fail-Safe, 20Mbps,

Profibus RS-485/RS-422 Transceivers

MAX3362: +3.3V, High-Speed, RS-485/RS-422

Transceiver in a SOT23 Package

MAX3280E–MAX3284E: ±15kV ESD-Protected,

52Mbps, +3V to +5.5V, SOT23, RS-485/RS-422,

True Fail-Safe Receivers

MAX3293/MAX3294/MAX3295: 20Mbps, +3.3V,

SOT23, RS-485/RS-422 Transmitters

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

o 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 Transceivers

MAX481/MAX483/MAX485/

MAX487–MAX491/MAX1487

Low-Power, Slew-Rate-Limited

RS-485/RS-422 Transceivers

For pricing, delivery, and ordering information, please contact Maxim Direct at

1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.

______________________________________________________________Selection Table

19-0122; Rev 10; 9/14

PART

NUMBER

HALF/FULL

DUPLEX

DATA

RATE

(Mbps)

SLEW-RATE

LIMITED

LOW-

POWER

SHUTDOWN

RECEIVER/

DRIVER

ENABLE

QUIESCENT

CURRENT

(μA)

NUMBER OF

RECEIVERS ON

BUS

COUNT

MAX481 Half 2.5 No Yes Yes 300 32 8

MAX483 Half 0.25 Yes Yes Yes 120 32 8

MAX485 Half 2.5 No No Yes 300 32 8

MAX487 Half 0.25 Yes Yes Yes 120 128 8

MAX488 Full 0.25 Yes No No 120 32 8

MAX489 Full 0.25 Yes No Yes 120 32 14

MAX490 Full 2.5 No No No 300 32 8

MAX491 Full 2.5 No No Yes 300 32 14

MAX1487 Half 2.5 No No Yes 230 128 8

Ordering Information appears at end of data sheet.

Summary of content (17 pages)

PAGE 1
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers General Description The MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 are low-power transceivers for RS-485 and RS422 communication. Each part contains one driver and one receiver. The MAX483, MAX487, MAX488, and MAX489 feature reduced slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, thus allowing error-free data transmission up to 250kbps.
PAGE 2
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC) .............................................................12V Control 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 +12.5V Receiver Input Voltage (A, B).................................-8V to +12.
PAGE 3
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers DC ELECTRICAL CHARACTERISTICS (continued) (VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.
PAGE 4
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487 (continued) (VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted.
PAGE 5
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 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.
PAGE 6
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 ____________________________Typical Operating Characteristics (continued) (VCC = 5V, TA = +25°C, unless otherwise noted.) OUTPUT CURRENT vs. DRIVER OUTPUT HIGH VOLTAGE 120 600 MAX481-08 -120 MAX481-07 140 MAX481/MAX485/MAX490/MAX491 SUPPLY CURRENT vs. TEMPERATURE MAX481/MAX485; DE = VCC, RE = X 80 60 40 20 500 SUPPLY CURRENT (μA) OUTPUT CURRENT (mA) -100 100 MAX481-11 OUTPUT CURRENT vs.
PAGE 7
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers ______________________________________________________________Pin Description PIN MAX481/MAX483/ MAX485/MAX487/ MAX1487 MAX488/ MAX490 MAX489/ MAX491 NAME NAME FUNCTION FUNCTION DIP/SO µMAX DIP/SO µMAX DIP/SO 1 3 2 4 2 RO Receiver Output: If A > B by 200mV, RO will be high; If A < B by 200mV, RO will be low. 2 4 — — 3 RE Receiver Output Enable.
PAGE 8
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers TOP VIEW VCC VCC 8 A RO 2 7 B DI 3 6 Z 5 Y VCC 1 GND 4 R D MAX488 MAX490 1 5 Y DI 3 Rt D 6 Z R RO DIP/SO 8 A B 1 A 2 VCC 3 RO 4 8 MAX488 MAX490 RO Z 7 Y 6 GND 5 DI 2 Rt R D 7 DI B 4 GND μMAX GND NOTE: TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE. Figure 2. MAX488/MAX490 Pin Configuration and Typical Operating Circuit TOP VIEW DE 4 N.C.
PAGE 9
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers _________________________________________________________________Test Circuits Y R TEST POINT RECEIVER OUTPUT CRL 15pF VOD R 1kΩ VCC S1 1kΩ VOC S2 Z Figure 4. Driver DC Test Load 3V DE CL1 Y DI Figure 5. Receiver Timing Test Load 500Ω A RDIFF VID RO B Z S1 VCC OUTPUT UNDER TEST CL S2 RE CL2 Figure 6.
PAGE 10
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers _______________________________________________________Switching Waveforms 3V 3V DI 1.5V DE 1.5V 0V 1.5V 1.5V 0V tPHL tPLH 1/2 VO tLZ tZL(SHDN), tZL Y, Z Z VO 1/2 VO VO VDIFF 0V -VO 2.3V OUTPUT NORMALLY LOW VOL Y VDIFF = V (Y) - V (Z) VOH - 0.5V 2.3V 90% tR OUTPUT NORMALLY HIGH Y, Z 90% 10% VOL + 0.5V 0V 10% tZH(SHDN), tZH tF tHZ tSKEW = | tPLH - tPHL | Figure 8.
PAGE 11
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 10dB/div 10dB/div 0Hz 5MHz 500kHz/div Figure 12. Driver Output Waveform and FFT Plot of MAX481/ MAX485/MAX490/MAX491/MAX1487 Transmitting a 150kHz Signal Low-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.
PAGE 12
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 100pF Z TTL IN tR, tF < 6ns B R D Y R = 54Ω RECEIVER OUT A 100pF Figure 14. Receiver Propagation Delay Test Circuit A B VCC = 5V TA = +25°C 500mV/div B VCC = 5V TA = +25°C 500mV/div A RO 2V/div 2V/div RO 20ns/div 20ns/div Figure 15.
PAGE 13
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers Line Length vs. Data Rate The 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 120Ω loads.
PAGE 14
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers A R RO RE Y 120Ω 120Ω D B Z Z B DI DE DE DI 120Ω 120Ω D Y Z Y B A Y Z R A DE RE RO A R D D DI B RE RO R DI MAX488–MAX491 DE RE RO NOTE: RE AND DE ON MAX489/MAX491 ONLY. Figure 22. MAX488–MAX491 Full-Duplex RS-485 Network Isolated RS-485 MAX488–MAX491 For isolated RS-485 applications, see the MAX253 and MAX1480 data sheets.
PAGE 15
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers _______________Ordering Information __Ordering Information (continued) PART MAX481CPA TEMP RANGE 0°C to +70°C 8 Plastic DIP MAX481CSA 0°C to +70°C 8 SO MAX481CUA 0°C to +70°C 8 µMAX MAX481C/D 0°C to +70°C Dice* MAX481EPA -40°C to +85°C 8 Plastic DIP MAX481ESA MAX481MJA MAX483CPA -40°C to +85°C -55°C to +125°C 0°C to +70°C 8 SO 8 CERDIP 8 Plastic DIP MAX483CSA 0°C to +70°C MAX483CUA MAX48
PAGE 16
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers Package Information For the latest package outline information and land patterns, go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. 16 PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.
PAGE 17
MAX481/MAX483/MAX485/ MAX487–MAX491/MAX1487 Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers Revision History PAGES CHANGED REVISION NUMBER REVISION DATE 0 1/93 Initial release. — 9 9/09 Changed column name in Selection Table to “Number of Receivers on Bus.” 1 10 9/14 Added MAX491MSD/PR and MAX491MSD/PR-T to data sheet. Updated Absolute Maximum Ratings.