SN54ABT16652, SN74ABT16652
16-BIT BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
SCBS215B FEBRUARY 1991 REVISED JANUARY 1997
1
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
D
Members of the Texas Instruments
Widebus
TM
Family
D
State-of-the-Art
EPIC-
B
TM
BiCMOS Design
Significantly Reduces Power Dissipation
D
Latch-Up Performance Exceeds 500 mA Per
JEDEC Standard JESD-17
D
Typical V
OLP
(Output Ground Bounce)
< 1 V at V
CC
= 5 V, T
A
= 25
C
D
Distributed V
CC
and GND Pin Configuration
Minimizes High-Speed Switching Noise
D
Flow-Through Architecture Optimizes PCB
Layout
D
High-Drive Outputs (32-mA I
OH
, 64-mA I
OL
)
D
Package Options Include Plastic 300-mil
Shrink Small-Outline (DL) Package and
380-mil Fine-Pitch Ceramic Flat (WD)
Package Using 25-mil Center-to-Center
Spacings
description
The 'ABT16652 are 16-bit bus transceivers that
consist of D-type flip-flops and control circuitry
arranged for multiplexed transmission of data
directly from the data bus or from the internal
storage registers. These devices can be used as
two 8-bit transceivers or one 16-bit transceiver.
Output-enable (OEAB and OEBA) inputs are
provided to control the transceiver functions.
Select-control (SAB and SBA) inputs are provided
to select whether real-time or stored data is
transferred. 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 'ABT16652.
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.
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.
Widebus and EPIC-
B are trademarks of Texas Instruments Incorporated.
SN54ABT16652 . . . WD PACKAGE
SN74ABT16652 . . . DL PACKAGE
(TOP VIEW)
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1OEAB
1CLKAB
1SAB
GND
1A1
1A2
V
CC
1A3
1A4
1A5
GND
1A6
1A7
1A8
2A1
2A2
2A3
GND
2A4
2A5
2A6
V
CC
2A7
2A8
GND
2SAB
2CLKAB
2OEAB
1OEBA
1CLKBA
1SBA
GND
1B1
1B2
V
CC
1B3
1B4
1B5
GND
1B6
1B7
1B8
2B1
2B2
2B3
GND
2B4
2B5
2B6
V
CC
2B7
2B8
GND
2SBA
2CLKBA
2OEBA
SN54ABT16652, SN74ABT16652
16-BIT BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
SCBS215B FEBRUARY 1991 REVISED JANUARY 1997
2
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
description (continued)
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).
The SN54ABT16652 is characterized for operation over the full military temperature range of 55
C to 125
C.
The SN74ABT16652 is characterized for operation from 40
C to 85
C.
FUNCTION TABLE
INPUTS
DATA I/O
OPERATION OR FUNCTION
OEAB
OEBA
CLKAB
CLKBA
SAB
SBA
A1A8
B1B8
OPERATION OR FUNCTION
L
H
H or L
H or L
X
X
Input
Input
Isolation
L
H
X
X
Input
Input
Store A and B data
X
H
H or L
X
X
Input
Unspecified
Store A, hold B
H
H
X
X
Input
Output
Store A in both registers
L
X
H or L
X
X
Unspecified
Input
Hold A, store B
L
L
X
X
Output
Input
Store B in both registers
L
L
X
X
X
L
Output
Input
Real-time B data to A bus
L
L
X
H or L
X
H
Output
Input
Stored B data to A bus
H
H
X
X
L
X
Input
Output
Real-time A data to B bus
H
H
H or L
X
H
X
Input
Output
Stored A data to B bus
H
L
H or L
H or L
H
H
Output
Output
Stored A data to B bus and
stored B data to A bus
The data-output functions may be enabled or disabled by a variety of level combinations at OEAB or OEBA. Data-input functions are always
enabled; i.e., data at the bus terminals is stored on every low-to-high transition of the clock inputs.
Select control = L; clocks can occur simultaneously.
Select control = H; clocks must be staggered to load both registers.
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