16-bit Registered Transceivers with 3-state Outputs
The HD74ALVCH16543 can be used as two 8-bit transceivers or one 16-bit transceiver. 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 CEBA, LEBA, and OEBA. Active
bus hold circuitry is provided to hold unused or floating data inputs at a valid logic level.
• VCC = 2.3 V to 3.6 V
• Typical VOL ground bounce < 0.8 V (@VCC = 3.3 V, Ta = 25°C)
• Typical VOH undershoot > 2.0 V (@VCC = 3.3 V, Ta = 25°C)
• High output current ±24 mA (@VCC = 3.0 V)
• Bus hold on data inputs eliminates the need for external pullup / pulldown resistors