Two-Way Asynchronous Communication

Between Data Buses

pnp Inputs Reduce dc Loading

Package Options Include Plastic

Small-Outline (D) Packages, Ceramic Chip

Carriers (FK), and Standard Plastic (N) and

Ceramic (J) 300-mil DIPs

description

These quadruple bus transceivers are designed

for asynchronous two-way communication

between data buses. The control-function

implementation allows for maximum flexibility in

timing. These devices allow data transmission

from the A bus to the B bus or from the B bus to the

A bus depending upon the logic levels at the

output-enable (OEBA and OEAB) inputs. The

output-enable inputs can be used to disable the

device so that the buses are effectively isolated.

The dual-enable configuration gives the

quadruple bus transceivers the capability to store

data by simultaneously enabling OEBA and

OEAB. Each output reinforces its input in this

transceiver configuration. When both control

inputs are enabled and all other data sources to

the two sets of bus lines are at high impedance,

both sets of bus lines (eight in all) retain their

states. The 4-bit codes appearing on the two sets

of buses are identical.

The SN54ALS243A is characterized for operation over the full military temperature range of −55°C to 125°C.

The SN74ALS243A is characterized for operation from 0°C to 70°C.