SN74ALS563BN.A中文资料德州仪器数据手册PDF规格书

3-State Buffer-Type Outputs Drive Bus

Lines Directly

Bus-Structured Pinout

description/ordering information

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 inverse 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.