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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

♦ 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

♦ 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-855/RS-422 Transmitters

♦ For Multiple Transceiver Applications

MAX3030E–MAX3033E: ±15kV ESD-Protected,

+3.3V, Quad RS-422 Transmitters

♦ For Fail-Safe Applications

MAX3080–MAX3089: Fail-Safe, High-Speed

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

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 Transceivers

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487

Low-Power, Slew-Rate-Limited

RS-485/RS-422 Transceivers

________________________________________________________________ Maxim Integrated Products 1

______________________________________________________________Selection Table

19-0122; Rev 8; 10/03

MAX481

MAX483

MAX485

MAX487

MAX488

MAX489

MAX490

MAX491

MAX1487

PART

NUMBER

HALF/FULL

DUPLEX

DATA RATE

(Mbps)

SLEW-RATE

LIMITED

LOW-POWER

SHUTDOWN

RECEIVER/

DRIVER

ENABLE

QUIESCENT

CURRENT

(µA)

NUMBER OF

TRANSMITTERS

ON BUS

COUNT

Half

Full

Half

2.5

0.25

2.5

0.25

2.5

Yes

300

120

300

120

300

230

128

Ordering Information appears at end of data sheet.

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487

Low-Power, Slew-Rate-Limited

RS-485/RS-422 Transceivers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

Supply Voltage (V

).............................................................12V

Control Input Voltage (

RE, DE)...................-0.5V to (V

+ 0.5V)

Driver Input Voltage (DI).............................-0.5V to (V

+ 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

+0.5V)

Continuous Power Dissipation (T

= +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).................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_ _MJ_/MAX1487MJA ...........................-55°C to +125°C

Storage Temperature Range .............................-65°C to +160°C

Lead Temperature (soldering, 10sec) .............................+300°C

DC ELECTRICAL CHARACTERISTICS

= 5V ±5%, T

= 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.

= -7V

= 12V

= -7V

= 12V

Input Current

(A, B)

IN2

kΩ48-7V ≤ V

≤ 12V, MAX487/MAX1487

Receiver Input Resistance

-7V ≤ V

≤ 12V, all devices except

MAX487/MAX1487

R = 27Ω (RS-485), Figure 4

0.4V ≤ V

≤ 2.4V

R = 50Ω (RS-422)

= 4mA, V

= -200mV

= -4mA, V

= 200mV

= 0V

-7V ≤ V

≤ 12V

DE, DI, RE

MAX487/MAX1487,

DE = 0V, V

= 0V or 5.25V

DE, DI, RE

R = 27Ω or 50Ω, Figure 4

DE = 0V;

= 0V or 5.25V,

all devices except

MAX487/MAX1487

CONDITIONS

kΩ12

µA±1I

OZR

Three-State (high impedance)

Output Current at Receiver

0.4V

Receiver Output Low Voltage

3.5V

Receiver Output High Voltage

mV70∆V

Receiver Input Hysteresis

V-0.2 0.2

Receiver Differential Threshold

Voltage

-0.2

0.25

-0.8

1.0

1.5 5

OD2

Differential Driver Output

(with load)

V5V

OD1

Differential Driver Output (no load)

µA±2I

IN1

Input Current

V0.8V

Input Low Voltage

V2.0V

Input High Voltage

V0.2∆V

Change in Magnitude of Driver

Common-Mode Output Voltage

for Complementary Output States

V0.2∆V

Change in Magnitude of Driver

Differential Output Voltage for

Complementary Output States

V3V

Driver Common-Mode Output

Voltage

UNITSMIN TYP MAXSYMBOLPARAMETER

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487

Low-Power, Slew-Rate-Limited

RS-485/RS-422 Transceivers

_______________________________________________________________________________________ 3

SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487

= 5V ±5%, T

= T

MIN

to T

MAX

, unless otherwise noted.) (Notes 1, 2)

DC ELECTRICAL CHARACTERISTICS (continued)

= 5V ±5%, T

= T

MIN

to T

MAX

, unless otherwise noted.) (Notes 1, 2)

7950V ≤ V

≤ V

OSR

Receiver Short-Circuit Current

mA35 250-7V ≤ V

≤12V (Note 4)I

OSD2

Driver Short-Circuit Current,

= Low

mA35 250-7V ≤ V

≤12V (Note 4)I

OSD1

Driver Short-Circuit Current,

= High

MAX1487,

RE = 0V or V

250 400

350 650

10 30 60t

PHL

Driver Rise or Fall Time

Figures 6 and 8, R

DIFF

= 54Ω, C

= C

= 100pF

MAX490M, MAX491M

MAX490C/E, MAX491C/E 20 90 150

MAX481, MAX485, MAX1487

MAX490M, MAX491M

MAX490C/E, MAX491C/E

MAX481, MAX485, MAX1487

Figures 6 and 8, R

DIFF

= 54Ω,

= C

= 100pF

MAX481 (Note 5)

Figures 5 and 11, C

= 15pF, S2 closed

Figures 5 and 11, C

= 15pF, S1 closed

Figures 5 and 11, C

= 15pF, S2 closed

Figures 5 and 11, C

= 15pF, S1 closed

Figures 6 and 10, R

DIFF

= 54Ω,

= C

= 100pF

Figures 6 and 8,

DIFF

= 54Ω,

= C

= 100pF

Figures 6 and 10,

DIFF

= 54Ω,

= C

= 100pF

CONDITIONS

510t

SKEW

ns50 200 600t

SHDN

Time to Shutdown

Mbps2.5f

MAX

Maximum Data Rate

ns20 50t

Receiver Disable Time from High

10 30 60t

PLH

20 50t

Receiver Disable Time from Low

ns20 50t

Driver Input to Output

Receiver Enable to Output High

ns20 50t

Receiver Enable to Output Low

20 90 200

40 70t

SKD

Driver Disable Time from High

| t

PLH

- t

PHL

| Differential

Receiver Skew

ns40 70t

Driver Disable Time from Low

40 70t

Driver Enable to Output Low

31540

51525

31540

, t

20 90 200

Driver Output Skew to Output

PLH

, t

PHL

Receiver Input to Output

40 70t

Driver Enable to Output High

UNITSMIN TYP MAXSYMBOLPARAMETER

CONDITIONS UNITSMIN TYP MAXSYMBOLPARAMETER

230 400

300 500

MAX481/MAX485,

RE = 0V or V

500 900

MAX490/MAX491,

DE, DI, RE = 0V or V

300 500

MAX488/MAX489,

DE, DI, RE = 0V or V

120 250

DE = V

300 500DE = 0V

DE = V

DE = 0V

µA

MAX481/483/487, DE = 0V, RE = V

0.1 10I

SHDN

Supply Current in Shutdown

120 250

No-Load Supply Current

(Note 3)

DE = 5V

DE = 0V

MAX483

MAX487

MAX483/MAX487,

RE = 0V or V

Figures 7 and 9, C

= 100pF, S2 closed

Figures 7 and 9, C

= 100pF, S1 closed

Figures 7 and 9, C

= 15pF, S1 closed

Figures 7 and 9, C

= 15pF, S2 closed

µA

Part #	MAX490CUA
Description	RS-422/RS-485 Interface IC Low-Power, Slew-Rate-Limited RS
Category	IC
Availability	In Stock
Qty	12

Qty	Price
1 - 2	$13.81058
3 - 5	$10.98569
6 - 7	$10.35793
8 - 10	$9.62556
11 +	$8.57930

MAX490CUA

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Technical Document