SN54ALS563B - Octal D-type Transparent Latches With 3-State Outputs

These 8-bit D-type transparent latches feature 3-state outputs designed specifically for driving highly capacitive or relatively low-impedance loads. They are particularly suitable for implementing buffer registers, I/O ports, bidirectional bus drivers, and working registers.

While the latch-enable (LE) input is high, the Q outputs follow the complements of data (D) inputs. When LE is taken low, the outputs are latched at the inverses of the levels set up at the D inputs.

A buffered output-enable (OE)\ input places the eight outputs in either a normal logic state (high or low logic levels) or a high-impedance state. In the high-impedance state, the outputs neither load nor drive the bus lines significantly. The high-impedance state and increased high logic level provide the capability to drive bus lines without interface or pullup components.

OE\ does not affect internal operations of the latches. Old data can be retained or new data can be entered while the outputs are in the high-impedance state.

• 3-State Buffer-Type Outputs Drive Bus Lines Directly
• Bus-Structured Pinout