DS36276 FAILSAFE Multipoint Transceiver
July 1998
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
Truth Tables
Driver
Inputs
RE
X
X
X
DE
H
H
L
DI
H
L
X
H
L
Z
Outputs
DO/RI
DO /RI
L
H
Z
DS011383-1
Receiver
Inputs
RE
L
L
H
DE
L
L
X
RI–RI
≥0V
≤−500
mV
X
Output
RO
H
L
Z
Order Number DS36276M
See NS Package Number M08A
Receiver FAILSAFE
Inputs
RE
L
L
H
DE
L
L
X
RI–RI
SHORTED
OPEN
X
Output
RO
H
H
Z
TRI-STATE
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is a registered trademark of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation
DS011383
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
