54AC646
Octal Transceiver/Register with TRI-STATE
®
Outputs
General Description
The ’AC646 consist of registered bus transceiver circuits,
with outputs, D-type flip-flops and control circuitry providing
multiplexed transmission of data directly from the input bus
or from the internal storage registers. Data on the A or B bus
will be loaded into the respective registers on the
LOW-to-HIGH transition of the appropriate clock pin (CPAB
or CPBA). The four fundamental data handling functions
available are illustrated in Figures 1, 2, 3, 4.
Features
n Independent registers for A and B buses
n Multiplexed real-time and stored data transfers
n TRI-STATE outputs
n 300 mil slim dual-in-line package
n Outputs source/sink 24 mA
n ’ACT646 has TTL compatible inputs
n Standard Microcircuit Drawing (SMD)
— ’AC646: 5962-89682
Logic Symbols
Pin Names Description
A
0
–A
7
Data Register A Inputs
Data Register A Outputs
B
0
–B
7
Data Register B Inputs
Data Register B Outputs
CPAB, CPBA Clock Pulse Inputs
SAB, SBA Transmit/Receive Inputs
G Output Enable Input
DIR Direction Control Input
TRI-STATE
®
is a registered trademark of National Semiconductor Corporation.
FACT
®
is a registered trademark of Fairchild Semiconductor Corporation.
DS100231-1
IEEE/IEC
DS100231-2
August 1998
54AC646
Octal
T
ransceiver/Register
with
TRI-ST
A
T
E
Outputs
© 1998 National Semiconductor Corporation DS100231 www.national.com