Single 5-V Supply

High-Input-Impedance, High-Threshold

Receivers

Common Driver Strobe

TTL-Compatible Driver and Strobe Inputs

With Clamp Diodes

High-Speed Operation

100-mA Open-Collector Driver Outputs

Four Independent Channels

TTL-Compatible Receiver Output

description

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 driveroutput

current and the high receiver-input

impedance, a very large number (typically

hundreds) of transceivers may be connected to a

single data bus.

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.