3-State Buffer-Type Outputs Drive Bus

Lines Directly

• Bus-Structured Pinout

• True Logic Outputs

• Package Options Include Plastic

Small-Outline (DW) Packages, Ceramic

Chip Carriers (FK), Standard Plastic (N) and

Ceramic (J) 300-mil DIPs, and Ceramic Flat

(W) Packages

description

These octal 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, outputs

(Q) respond to the data (D) inputs. When LE is low,

the outputs are latched to retain the data that was

set up.

A buffered output-enable (OE) input can be used

to place the eight outputs in either a normal logic

state (high or low) 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 the increased drive

provide the capability to drive bus lines without

interface or pullup components.

OE does not affect internal operation of the

latches. Old data can be retained or new data can

be entered while the outputs are in the

high-impedance state.

The SN54ALS573C and SN54AS573A are characterized for operation over the full military temperature range

of −55°C to 125°C. The SN74ALS573C and SN74AS573A are characterized for operation from 0°C to 70°C.