_________________General Description

The MAX1480EA/MAX1480EC/MAX1490EA/MAX1490EB

are complete, electrically isolated, RS-485/RS-422 data

communications interface solutions in a hybrid microcir-

cuit. The RS-485/RS-422 I/O pins are protected against

±15kV electrostatic discharge (ESD) shocks, without

latchup. Transceivers, optocouplers, and a transformer

provide a complete interface in a standard DIP package.

A single +5V supply on the logic side powers both sides

of the interface.

The MAX1480EC/MAX1490EB feature reduced-slew-rate

drivers that minimize EMI and reduce reflections caused

by improperly terminated cables, allowing error-free data

transmission at data rates up to 160kbps. The

MAX1480EA/MAX1490EA driver slew rate is not limited,

allowing transmission rates up to 2.5Mbps. The

MAX1480EA/MAX1480EC are designed for half-duplex

communication, while the MAX1490EA/MAX1490EB fea-

ture full-duplex communication.

Drivers are short-circuit current limited and protected

against excessive power dissipation by thermal shut-

down circuitry that places the driver outputs into a high-

impedance state. The receiver input has a fail-safe

feature that guarantees a known output (RO low for the

MAX1480EA/MAX1480EC, RO high for the MAX1490EA/

MAX1490EB) if the input is open circuit.

The MAX1480EA/MAX1480EC/MAX1490EA/MAX1490EB

lated outputs meet all RS-485/RS-422 specifications. The

MAX1480EA/MAX1480EC are available in a 28-pin DIP

package, and the MAX1490EA/MAX1490EB are available

in a 24-pin DIP package.

.

________________________Applications

Isolated RS-485/RS-422 Data Interface

Transceivers for EMI-Sensitive Applications

Industrial-Control Local Area Networks

Automatic Test Equipment

HVAC/Building Control Networks

Telecom

____________________________Features

(1min)

o ±15kV ESD Protection on I/O Pins

o Slew-Rate Limited for Errorless Data

Transmission (MAX1480EC/MAX1490EB)

o High-Speed, Isolated, 2.5Mbps RS-485/RS-422

Interface (MAX1480EA/MAX1490EA)

o Full-Duplex Data Communication

(MAX1490EA/MAX1490EB)

o Single +5V Supply

o Current Limiting and Thermal Shutdown for

Driver Overload Protection

o Standard 0.6in DIP Packages

28-Pin DIP (MAX1480EA/MAX1480EC)

24-Pin DIP (MAX1490EA/MAX1490EB)

±15kV ESD-Protected, Isolated RS-485/RS-422

Data Interfaces

________________________________________________________________ Maxim Integrated Products

1

Pin Configurations

1

24

23

22

21

20

19

18

17

2

3

4

5

6

7

8

AC1

AC2

ISO RO DRV

D2

D1

A

B

Z

Y

SD

FS

GND1

16

15

14

13

9

10

11

12

ISO COM1

ISO DI DRV

ISO RO LED

GND2

RO

DI

DIP

MAX1490EA/

MAX1490EB

TOP VIEW

ISOLATION BARRIER

19-1940; Rev 0; 4/01

MAX1480EACPI

MAX1480EAEPI

-40°C to +85°C

0°C to +70°C

TEMP. RANGE

PIN-PACKAGE

28 Wide Plastic DIP*

28 Wide Plastic DIP*

_______________Ordering Information

Ordering Information continued at end of data sheet.

up to 250kbps.

*See Reliability section at end of data sheet.

Pin Configurations continued at end of data sheet.

Selector Guide appears at end of data sheet.

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

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