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.