54ABT646 Octal Transceivers and Registers with TRI-STATE Outputs
July 1998
54ABT646
Octal Transceivers and Registers with TRI-STATE
®
Outputs
General Description
The ’ABT646 consists of bus transceiver circuits with
TRI-STATE, D-type flip-flops, and control circuitry arranged
for multiplexed transmission of data directly from the input
bus or from the internal registers. Data on the A or B bus will
be clocked into the registers as the appropriate clock pin
goes to a high logic level. Control OE and direction pins are
provided to control the transceiver function. In the trans-
ceiver mode, data present at the high impedance port may
be stored in either the A or the B register or in both. The se-
lect controls can multiplex stored and real-time (transparent
mode) data. The direction control determines which bus will
receive data when the enable control OE is Active LOW. In
the isolation mode (control OE HIGH), A data may be stored
in the B register and/or B data may be stored in the A regis-
ter.
Features
n
Independent registers for A and B buses
n
Multiplexed real-time and stored data
n
A and B output sink capability of 48 mA, source
capability of 24 mA
n
Guaranteed multiple output switching specifications
n
Output switching specified for both 50 pF and 250 pF
loads
n
Guaranteed simultaneous switching noise level and
dynamic threshold performance
n
Guaranteed latchup protection
n
High impedance glitch free bus loading during entire
power up and power down cycle
n
Nondestructive hot insertion capability
n
Standard Microcircuit Drawing (SMD) 5962-9457701
Ordering Code
Military
54ABT646J-QML
54ABT646W-QML
54ABT646E-QML
Package Number
J24A
W24C
E28A
24-Lead Cerpack
28-Lead Ceramic Leadless Chip Carrier, Type C
Package Description
24-Lead Ceramic Dual-In-Line
TRI-STATE
®
is a registered trademark of National Semiconductor Corporation.
© 1998 National Semiconductor Corporation
DS100209
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
