SN54F621, SN74F621
OCTAL BUS TRANSCEIVERS
WITH OPEN-COLLECTOR OUTPUTS

SDFS004B - D2932, MARCH 1987 - REVISED OCTOBER 1993

features

• Local Bus-Latch Capability
• Noninverting Logic
• Package Options Include Plastic Small-Outline Packages, Ceramic Chip Carriers, and Standard Plastic and Ceramic 300-mil DIPs

description

These octal bus transceivers are designed for asynchronous 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 (OEAB and ) 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 transceivers the capability of storing data by simultaneously enabling OEAB and . Each output reinforces its input in this configuration. When both OEAB and are enabled and all other data sources to the two sets of bus lines are at high impedance, both sets of bus lines (16 in all) will remain at their last states.

The SN54F621 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74F621 is characterized for operation from 0°C to 70°C.