RS-485/RS-422 Transceivers with Preemphasis

for High-Speed, Long-Distance Communication

________________________________________________________________

Maxim Integrated Products

1

19-1405; Rev 1; 4/99

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.

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________________General Description

The MAX3291/MAX3292 high-speed RS-485/RS-422

transceivers feature driver preemphasis circuitry, which

extends the distance and increases the data rate of reli-

able communication by reducing intersymbol interfer-

ence (ISI) caused by long cables. The MAX3291 is

programmable for data rates of 5Mbps to 10Mbps,

while the MAX3292 is programmable for data rates up

to 10Mbps by using a single external resistor.

The MAX3291/MAX3292 are full-duplex devices that

operate from a single +5V supply and offer a low-cur-

rent shutdown mode that reduces supply current to

100nA. They feature driver output short-circuit current

limiting and a fail-safe receiver input that guarantees a

logic-high output if the input is open circuit. A 1/4-unit-

load receiver input impedance allows up to 128 trans-

ceivers on the bus.

________________________Applications

Long-Distance, High-Speed RS-485/RS-422

Communications

Telecommunications

Industrial-Control Local Area Networks

____________________________Features

o Preemphasis Increases the Distance and Data

Rate of Reliable RS-485/RS-422 Communication

o Data Rate

Optimized for 5Mbps to 10Mbps (MAX3291)

Programmable up to 10Mbps (MAX3292)

o 100nA Low-Current Shutdown Mode

o Allow Up to 128 Transceivers on the Bus

o -7V to +12V Common-Mode Input Voltage Range

o Pin-Compatible with ’75180, MAX489, MAX491

MAX3080, MAX3083, MAX3086, MAX1482

2

PEE

(PSET)

12

13

14

1

1

µF

7(6)

GND

11

10

9

( ) ARE FOR MAX3292

* MAX3292 ONLY

IMPEDANCE OF THE CABLE

RO

RE

DE

DI

3

4

5

9

5

13

7(6)

GND

4

3

DI

DE

RE

RO

2

10

11

12

PEE

(PSET)

14

1

1

µF

MAX3291

MAX3292

MAX3291

MAX3292

A

B

Z

Y

Y

Z

B

A

Typical Operating Circuit and Functional Diagram

PART

MAX3291CSD

MAX3291CPD

MAX3291ESD

-40°C to +85°C

0°C to +70°C

0°C to +70°C

TEMP. RANGE

PIN-PACKAGE

14 SO

14 Plastic DIP

14 SO

_______________Ordering Information

MAX3291EPD

-40°C to +85°C

14 Plastic DIP

MAX3292CSD

MAX3292CPD

MAX3292ESD

-40°C to +85°C

0°C to +70°C

0°C to +70°C

14 SO

14 Plastic DIP

14 SO

MAX3292EPD

-40°C to +85°C

14 Plastic DIP

Pin Configuration appears at end of data sheet.