General Description

The MAX3535E/MXL1535E isolated RS-485/RS-422 full-

tion between the RS-485/RS-422 side and the processor

or control logic side. These devices allow fast,

1000kbps communication across an isolation barrier

when the common-mode voltages (i.e., the ground

potentials) on either side of the barrier are subject to

large differences. Isolation is achieved through integrat-

ed high-voltage capacitors. The MAX3535E/MXL1535E

also feature a 420kHz transformer driver that allows

power transfer to the RS-485 side using an external

transformer.

The MAX3535E/MXL1535E include one differential driver,

one receiver, and internal circuitry to send the RS-485

signals and control signals across the isolation barrier

(including the isolation capacitors). The MAX3535E/

MXL1535E RS-485 receivers are 1/8 unit load, allowing

up to 256 devices on the same bus.

The MAX3535E/MXL1535E feature true fail-safe circuitry.

The driver outputs and the receiver inputs are protected

from ±15kV electrostatic discharge (ESD) on the inter-

face side, as specified in the Human Body Model (HBM).

The MAX3535E/MXL1535E feature driver slew-rate

select that minimizes electromagnetic interference (EMI)

and reduces reflections. The driver outputs are short-cir-

cuit and overvoltage protected. Other features are hot-

swap capability and isolation-barrier fault detection.

The MAX3535E operates with a single +3V to +5.5V

power supply. The improved secondary supply range of

the MAX3535E allows the use of step-down transformers

for +5V operation, resulting in considerable power sav-

ings. The MXL1535E operates with a single +4.5V to

+5.5V power supply. The MXL1535E is a function-/pin-

compatible improvement of the LTC1535. The

MAX3535E/MXL1535E are available over the commer-

cial 0°C to +70°C and extended -40°C to +85°C temper-

ature ranges.

Applications

Isolated RS-485 Systems

Systems with Large Common-Mode Voltages

Industrial-Control Local Area Networks

Telecommunications Systems

Features

High-Voltage Capacitors

♦ 1000kbps Full-Duplex RS-485/RS-422

Communication

♦ +3V to +5.5V Power-Supply Voltage Range

(MAX3535E)

♦ +4.5V to +5.5V Power-Supply Voltage Range

(MXL1535E)

♦ 1/8 Unit Receiver Load, Allowing 256 Devices on

Bus

♦ ±15kV ESD Protection Using HBM

♦ Pin-Selectable Slew-Rate Limiting Controls EMI

♦ Hot-Swap-Protected Driver-Enable Input

♦ Undervoltage Lockout

♦ Isolation-Barrier Fault Detection

♦ Short-Circuit Protected

♦ Thermal Shutdown

♦ Open-Line and Shorted-Line Fail-Safe Receiver

Inputs

Transceivers with ±15kV ESD Protection

________________________________________________________________ Maxim Integrated Products

1

28

27

26

25

18

17

16

15

1

2

3

4

11

12

13

14

RO1

RE

DE

DI

B

SLO

RO2

A

PINS 5–10 and 19–24 ARE REMOVED FROM THE PACKAGE

Y

Z

GND2

GND1

ST2

ST1

WIDE SO

TOP VIEW

MAX3535E

MXL1535E

PART

TEMP RANGE

PIN-

PACKAGE

POWER-

SUPPLY

RANGE

(V)

MAX3535ECWI

0°C to +70°C

28 Wide SO

+3.0 to +5.5

MAX3535EEWI

-40°C to +85°C

28 Wide SO

+3.0 to +5.5

MXL1535ECWI

0°C to +70°C

28 Wide SO

+4.5 to +5.5

MXL1535EEWI

-40°C to +85°C

28 Wide SO+4.5 to +5.5

Pin Configuration

Ordering Information

19-3270; Rev 0; 4/04

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.

Typical Application Circuit appears at end of data sheet.