Revised March 2000
Octal D-Type Transparent Latch with 3-STATE Outputs
These 8-bit registers feature totem-pole 3-STATE outputs
designed specifically for driving highly-capacitive or rela-
tively low-impedance loads. The high-impedance state and
increased HIGH-logic-level drive provide these registers
with the capability of being connected directly to and driv-
ing the bus lines in a bus-organized system without need
for interface or pull-up components. They are particularly
attractive for implementing buffer registers, I/O ports, bidi-
rectional bus drivers, and working registers.
The eight latches of the DM74AS573 are transparent D-
type latches, meaning that while the enable (G) is HIGH
the Q outputs will follow the data (D) inputs. When the
enable is taken LOW the output will be latched at the level
of the data that was set UP.
A buffered output control input can be used to place the
eight outputs in either a normal logic state (HIGH or LOW
logic levels) or a high-impedance state. In the high-imped-
ance state the outputs neither load nor drive the bus lines
The output control does not affect the internal operation of
the latches. That is, the old data can be retained or new
data can be entered even while the outputs are OFF.
The pin-out is arranged to ease printed circuit board layout.
All data inputs are on one side of the package while all the
outputs are on the other side.
s Switching specifications at 50 pF
s Switching specifications guaranteed over full tempera-
ture and VCC range
s Advanced oxide-isolated, ion-implanted Schottky TTL
s Functionally equivalent with DM74S373
s Improved AC performance over DM74S373 at approxi-
mately half the power
s 3-STATE buffer-type outputs drive bus lines directly
s Bus structured pinout
Order Number Package Number
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
© 2000 Fairchild Semiconductor Corporation DS006313