LTM2885

1

2885fa

For more information www.linear.com/LTM2885

TYPICAL APPLICATION

DESCRIPTION

RS485/RS422 µModule

Transceiver + Power

The LTM®2885 is a complete galvanically isolated

transceiver. No external components are required. A

single supply powers both sides of the interface through

an integrated, isolated, low noise, efficient 5V output

DC/DC converter.

Coupled inductors and an isolation power transformer

and the logic interface. This device is ideal for systems

wherethegroundloopisbrokenallowingforlargecommon

mode voltage variation. Uninterrupted communication is

guaranteed for common mode transients up to 50kV/μs.

Maximum data rates are 20Mbps or 250kbps in slew

limited mode. Transmit data, DI, and receive data, RO, are

implemented with event driven low jitter processing. The

receiver has a one-eighth unit load supporting up to 256

nodes per bus. A logic supply pin allows easy interfacing

with different logic levels from 1.62V to 5.5V, independent

of the main supply.

Enhanced ESD protection allows this part to withstand up

to ±15kV (human body model) on the transceiver interface

pins to isolated supplies and ±25kV through the isolation

barrier to logic supplies without latch-up or damage.

Isolated Half-Duplex RS485 μModule Transceiver

FEATURES

APPLICATIONS

n

n

Reinforced Insulation

n

Isolated DC Power: 5V at 200mA

n

No External Components Required

n

20Mbps or Low EMI 250kbps Data Rate

n

High ESD: ±15kV HBM on Transceiver Interface

n

High Common Mode Transient Immunity: 50kV/μs

n

Integrated Selectable 120Ω Termination

n

Extended Creepage and Clearance ~14.6mm

n

1.62V to 5.5V Logic Supply Pin for Flexible

Digital Interface

n

n

High Input Impedance Failsafe RS485 Receiver

n

Current Limited Drivers and Thermal Shutdown

n

Compatible with TIA/EIA-485-A and PROFIBUS

n

High Impedance Output During Internal Fault Condition

n

Low Current Shutdown Mode (< 10µA)

n

General Purpose CMOS Isolated Channel

n

22mm × 9mm × 5.16mm Surface Mount BGA Package

n

Isolated RS485/RS422 Interface

n

Industrial Networks

n

Breaking RS485 Ground Loops

n

Isolated PROFIBUS-DP Networks

2885 TA01a

TWISTED-PAIR

CABLE

A

5V

OUT

RO

TE

RE

DE

DI

GND

GND2

5V

LTM2885

B

Y

Z

PWR

LTM2885 Operating Through 100kV/μs CM Transients

L

, LT, LTC, LTM, Linear Technology, the Linear logo and µModule are registered trademarks of

Analog Devices, Inc. All other trademarks are the property of their respective owners.

2885 TA01b

5V/DIV

5V/DIV

20ns/DIV

300V/DIV

DI

MULTIPLE SWEEPS

OF COMMON MODE

TRANSIENTS

RO