The ′BCT543 octal transceiver contains two sets of D-type latches for temporary storage of data flowing in either direction. Separate latch-enable (LEAB or LEBA) and output-enable (OEAB or OEBA) inputs are provided for each register to permit independent control in either direction of data flow.
The A-to-B enable (CEAB) input must be low in order to enter data from A or to output data from B. If CEAB is low and LEAB is low, the A-to-B latches are transparent; a subsequent low-to-high transition of LEAB puts the A latches in the storage mode. With CEAB and OEAB both low, the 3-state B outputs are active and reflect the data present at the output of the A latches. Data flow from B to A is similar but requires using the CEBA, LEBA, and OEBA inputs.
The SN54BCT543 is characterized for operation over the full military temperature range of −55°C to 125°C. The SN74BCT543 is characterized for operation from 0°C to 70°C.