LTM2881_10 Datasheet, PDF (1/22 Pages) Linear Technology – Complete Isolated RS485/RS422 μModule Transceiver + Power

Features
n _{Isolated RS485/RS422 Transceiver: 2500VRMS}
n _{Isolated DC Power: 5V at Up to 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: 30kV/μs}
n _{Integrated Selectable 120Ω Termination}
n _{3.3V (LTM2881-3) or 5.0V (LTM2881-5) Operation}
n _{1.62V to 5.5V Logic Supply Pin for Flexible Digital Interface}
n _{Common Mode Working Voltage: 560VPEAK}
n _{High Input Impedance Failsafe RS485 Receiver}
n _{Current Limited Drivers and Thermal Shutdown}
n _{Compatible with TIA/EIA-485-A Specification}
n _{High Impedance Output During Internal Fault Condition}
n _{Low Current Shutdown Mode (< 10µA)}
n _{General Purpose CMOS Isolated Channel}
n _{Small, Low Profile (15mm × 11.25mm × 2.8mm)}
Surface Mount BGA and LGA Packages
Applications
n _{Isolated RS485/RS422 Interface}
n _{Industrial Networks}
n _{Breaking RS485 Ground Loops}
LTM2881
Complete Isolated
RS485/RS422 µModule
Transceiver + Power
Description
The LTM^®2881 is a complete galvanically isolated full-
duplex RS485/RS422 µModule^® 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
provide 2500V_RMS of isolation between the line transceiver
and the logic interface. This device is ideal for systems
where the ground loop is broken allowing for large com-
mon mode voltage variation. Uninterrupted communica-
tion is guaranteed for common mode transients greater
than 30kV/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 ±10kV through the isolation
barrier to logic supplies without latch-up or damage.
L, LT, LTC, LTM, Linear Technology, µModule and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
Isolated Half-Duplex RS485 μModule Transceiver
3.3V
V_CC
V_L
RO
RE
TE
DE
DI
GND
PWR
LTM2881
V_CC2
5V
A
B
GND2
Y
Z
2881 TA01
AVAILABLE CURRENT:
150mA (LTM2881-5)
100mA (LTM2881-3)
TWISTED-PAIR
CABLE
LTM2881 Operating Through 35kV/μs CM Transients
MULTIPLE SWEEPS
OF COMMON MODE
TRANSIENTS
500V/DIV
1V/DIV
1V/DIV
DI
RO
50ns/DIV
2881 TA01a
2881fa