h1_key

The x92FCT543T octal latched transceivers contain two sets of eight D-type latches with separate latch-enable (LEAB, LEBA) and output-enable (OEAB, OEBA) inputs for each set to permit independent control of input and output in either direction of data flow. For data flow from A to B, for example, the A-to-B enable (CEAB) input must be low in order to enter data from A or to take data from B, as indicated in the function table. With CEAB low, a low signal on the A-to-B latch-enable (LEAB) input makes the A-to-B latches transparent; a subsequent low-to-high transition of the LEAB signal puts the A latches in the storage mode and their outputs no longer change with the A inputs. With CEAB and OEAB low, the 3-state B-output buffers are active and reflect the data present at the output of the A latches. Control of data from B to A is similar, but uses CEBA, LEBA, and OEBA inputs.

These devices are fully specified for partial-power-down applications using I_off. The I_off circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.