QUADRUPLE BUS TRANSCEIVERS
SLLS079B – SEPTEMBER 1973 – REVISED MAY 1995
D Single 5-V Supply
D High-Input-Impedance, High-Threshold
D Common Driver Strobe
D TTL-Compatible Driver and Strobe Inputs
With Clamp Diodes
D High-Speed Operation
D 100-mA Open-Collector Driver Outputs
D Four Independent Channels
D TTL-Compatible Receiver Output
SN55138 . . . J OR W PACKAGE
SN75138 . . . D OR N PACKAGE
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.
SN55138 . . . FK PACKAGE
3 2 1 20 19
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.
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