SN54ABT652A, SN74ABT652A
OCTAL REGISTERED TRANSCEIVERS
WITH 3-STATE OUTPUTS

SCBS072F – JANUARY 1991 – REVISED MAY 1997
1POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
C0068 State-of-the-Art EPIC-II B BiCMOS Design
Significantly Reduces Power Dissipation
C0068 ESD Protection Exceeds 2000 V Per
MIL-STD-883, Method 3015; Exceeds 200 V
Using Machine Model (C = 200 pF, R = 0)
C0068 Latch-Up Performance Exceeds 500 mA Per
JEDEC Standard JESD-17
C0068 Typical V
OLP
(Output Ground Bounce)
< 1 V at V
CC
= 5 V, T
A
= 25°C
C0068 High-Drive Outputs (–32-mA I
OH
, 64-mA I
OL
)
C0068 Package Options Include Plastic
Small-Outline (DW), Shrink Small-Outline
(DB), and Thin Shrink Small-Outline (PW)
Packages, Ceramic Chip Carriers (FK),
Ceramic Flat (W) Package, and Plastic (NT)
and Ceramic (JT) DIPs
description
These devices consist of bus-transceiver circuits,
D-type flip-flops, and control circuitry arranged for
multiplexed transmission of data directly from the
data bus or from the internal storage registers.
Output-enable (OEAB and OEBA) inputs are
provided to control the transceiver functions.
Select-control (SAB and SBA) inputs are provided
to select either real-time or stored data for
transfer. The circuitry used for select control
eliminates the typical decoding glitch that occurs
in a multiplexer during the transition between
stored and real-time data. A low input selects
real-time data, and a high input selects stored
data. Figure 1 illustrates the four fundamental
bus-management functions that can be
performed with the ’ABT652A.
Data on the A- or B-data bus, or both, can be stored in the internal D-type flip-flops by low-to-high transitions
at the appropriate clock (CLKAB or CLKBA) inputs, regardless of the select- or enable-control inputs. When SAB
and SBA are in the real-time transfer mode, it is possible to store data without using the internal D-type flip-flops
by simultaneously enabling OEAB and OEBA. In this configuration, each output reinforces its input. When all
other data sources to the two sets of bus lines are at high impedance, each set of bus lines remains at its last
state.
To ensure the high-impedance state during power up or power down, OEBA should be tied to V
CC
through a
pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver
(B to A). OEAB should be tied to GND through a pulldown resistor; the minimum value of the resistor is
determined by the current-sourcing capability of the driver (A to B).
Copyright  1997, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
EPIC-II B is a trademark of Texas Instruments Incorporated.
SN54ABT652A . . . JT OR W PACKAGE
SN74ABT652A . . . DB, DW, NT, OR PW PACKAGE
(TOP VIEW)
SN54ABT652A . . . FK PACKAGE
(TOP VIEW)
3212827
12 13
5
6
7
8
9
10
11
25
24
23
22
21
20
19
OEBA
B1
B2
NC
B3
B4
B5
A1
A2
A2
NC
A4
A5
A6
426
14 15 16 17 18
A7 A8
GND
NC
B8 B7 B6
OEAB SAB CLKAB NC CLKBA SBA

V
CC
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
CLKAB
SAB
OEAB
A1
A2
A3
A4
A5
A6
A7
A8
GND
V
CC
CLKBA
SBA
OEBA
B1
B2
B3
B4
B5
B6
B7
B8
NC – No internal connection