54ACT399 Quad 2-Port Register
August 1998
54ACT399
Quad 2-Port Register
General Description
The 鈥橝C/ACT399 is the logical equivalent of a quad 2-input
multiplexer feeding into four edge-triggered flip-flops. A com-
mon Select input determines which of the two 4-bit words is
accepted. The selected data enters the flip-flop on the rising
edge of the clock.
Features
n
n
n
n
n
I
CC
reduced by 50%
Select inputs from two data sources
Fully positive edge-triggered operation
Outputs source/sink 24 mA
ACT399 has TTL-compatible inputs
Logic Symbols
Connection Diagrams
Pin Assignment
for DIP and Flatpak
DS100356-1
IEEE/IEC
DS100356-3
Pin Assignment
for LCC
DS100356-5
DS100356-2
Pin Names
S
CP
I
0a
鈥揑
0d
I
1a
鈥揑
1d
Q
a
鈥換
d
Description
Common Select Input
Clock Pulse Input
Data Inputs from Source 0
Data Inputs from Source 1
Register True Outputs
TRI-STATE
廬
is a registered trademark of National Semiconductor Corporation.
FACT
廬
is a registered trademark of Fairchild Semiconductor Corporation.
漏 1998 National Semiconductor Corporation
DS100356
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