Datasheet

DS36276
FAILSAFE Multipoint Transceiver
General Description
The DS36276 FAILSAFE Multipoint Transceiver is designed
for use on bi-directional differential busses. It is compatible
with existing TIA/EIA-485 transceivers, however, it offers an
additional feature not supported by standard transceivers.
The FAILSAFE feature guarantees the receiver output to a
known state when the Interface is in the following conditions:
Floating Line, Idle Line (no active drivers), and Line Fault
conditions (open or short). The receiver output is in a HIGH
state for the following conditions: OPEN Inputs, Terminated
Inputs (50Ω), and SHORTED Inputs.
FAILSAFE is a highly desirable feature when the transceiv-
ers are used with Asynchronous Controllers such as UARTs.
Features
n FAILSAFE receiver, RO = HIGH for:
— OPEN inputs
— Terminated inputs
— SHORTED inputs
n Compatible with popular interface standards:
— TIA/EIA-485 (RS-485)
— TIA/EIA-422-A (RS-422-A)
— CCITT Recommendation V.11
n Bi-Directional Transceiver
— Designed for multipoint transmission
n Separate driver input, driver enable, receiver enable,
and receiver output for maximum flexibility
n Wide bus common mode range
— (−7V to +12V)
n Pin compatible with: DS75176B, DS96176, DS3695 and
SN75176A and B
n Available in SOIC package
Connection and
Logic Diagram
Driver
Inputs Outputs
RE
DE DI DO/RI DO /RI
XHH H L
XHL L H
XLX Z Z
Receiver
Inputs Output
RE
DE RI–RI RO
LL ≥0V H
LL≤−500 mV L
HX X Z
Receiver FAILSAFE
Inputs Output
RE
DE RI–RI RO
L L SHORTED H
L L OPEN H
HX X Z
TRI-STATE
®
is a registered trademark of National Semiconductor Corporation.
DS011383-1
Order Number DS36276M
See NS Package Number M08A
July 1998
DS36276 FAILSAFE Multipoint Transceiver
© 2001 National Semiconductor Corporation DS011383 www.national.com