SN55138, SN75138
QUADRUPLE BUS TRANSCEIVERS
SLLS079B – SEPTEMBER 1973 – REVISED MAY 1995
SN55138 . . . J OR W PACKAGE
SN75138 . . . D OR N PACKAGE
Single 5-V Supply
High-Input-Impedance, High-Threshold
Receivers
(TOP VIEW)
Common Driver Strobe
1
2
3
4
5
6
7
8
16
V
CC
15 4B
GND
1B
TTL-Compatible Driver and Strobe Inputs
With Clamp Diodes
14
13
12
11
10
9
4R
4D
S
1R
1D
High-Speed Operation
2D
100-mA Open-Collector Driver Outputs
Four Independent Channels
TTL-Compatible Receiver Output
3D
3R
3B
2R
2B
GND
description
SN55138 . . . FK PACKAGE
(TOP VIEW)
The SN55138 and SN75138 quadruple bus
transceivers are designed for two-way data
communication over single-ended transmission
lines. Each of the four identical channels consists
of a driver with TTL inputs and a receiver with a
TTL output. The driver open-collector output is
designed to handle loads up to 100-mA open
collector. The receiver input is internally
connected to the driver output, and has a high
impedance to minimize loading of the
transmission line. Because of the high driver-
output current and the high receiver-input
impedance, a very large number (typically
hundreds) of transceivers may be connected to a
single data bus.
3
2
1
20 19
18
4R
4D
NC
S
1R
1D
NC
2D
2R
4
5
6
7
8
17
16
15
14
3D
9 10 11 12 13
NC – No internal connection
The receiver design also features a threshold of 2.3 V (typical), providing a wider noise margin than would be
possible with a receiver having the usual TTL threshold. A strobe turns off all drivers (high impedance) but does
not affect receiver operation. These circuits are designed for operation from a single 5-V supply and include a
provision to minimize loading of the data bus when the power-supply voltage is zero.
The SN55138 is characterized for operation over the full military temperature range of –55°C to 125°C. The
SN75138 is characterized for operation from 0°C to 70°C.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright 1995, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
1
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