Bidirectional Bus Transceivers in

High-Density 20-Pin Packages

Choice of True or Inverting Logic

A-Bus Outputs Are Open Collector;

B-Bus Outputs Are 3 State

Package Options Include Plastic

Small-Outline (DW) Packages and

Standard Plastic (N) 300-mil DIPs

description

These octal bus transceivers are designed for asynchronous two-way communication between open-collector

and 3-state buses. The devices transmit data from the A bus (open-collector) to the B bus (3 state) or from the

B bus to the A bus, depending on the logic level at the direction-control (DIR) input. The output-enable (OE) input

can be used to disable the device so the buses are isolated.

The -1 version of SN74ALS638A is identical to the standard version, except that the recommended maximum

IOL is increased to 48 mA.

The SN74ALS638A, SN74ALS639A, SN74AS638A, and SN74AS639 are characterized for operation from 0°C

to 70°C.