SN54ALS243A, SN74ALS243A
QUADRUPLE BUS TRANSCEIVERS
WITH 3ĆSTATE OUTPUTS
SDAS069B − DECEMBER 1982 − REVISED DECEMBER 1994
•
•
•
SN54ALS243A . . . J PACKAGE
SN74ALS243A . . . D OR N PACKAGE
(TOP VIEW)
Two-Way Asynchronous Communication
Between Data Buses
pnp Inputs Reduce dc Loading
Package Options Include Plastic
Small-Outline (D) Packages, Ceramic Chip
Carriers (FK), and Standard Plastic (N) and
Ceramic (J) 300-mil DIPs
OEAB
NC
A1
A2
A3
A4
GND
description
These quadruple bus transceivers are designed
for asynchronous two-way communication
between data buses. The control-function
implementation allows for maximum flexibility in
timing. These devices allow data transmission
from the A bus to the B bus or from the B bus to the
A bus depending upon the logic levels at the
output-enable (OEBA and OEAB) inputs. The
output-enable inputs can be used to disable the
device so that the buses are effectively isolated.
1
2
13
3
VCC
OEBA
NC
B1
B2
B3
B4
14
12
4
11
5
10
6
9
7
8
NC
OEAB
NC
VCC
OEBA
SN54ALS243A . . . FK PACKAGE
(TOP VIEW)
A1
NC
A2
NC
A3
3 2 1 20 19
18
5
17
6
16
7
15
8
14
9 10 11 12 13
NC
NC
B1
NC
B2
A4
GND
NC
B4
B3
The dual-enable configuration gives the
quadruple bus transceivers the capability to store
data by simultaneously enabling OEBA and
OEAB. Each output reinforces its input in this
transceiver configuration. When both control
inputs are enabled and all other data sources to
the two sets of bus lines are at high impedance,
both sets of bus lines (eight in all) retain their
states. The 4-bit codes appearing on the two sets
of buses are identical.
4
NC − No internal connection
The SN54ALS243A is characterized for operation over the full military temperature range of − 55°C to 125°C.
The SN74ALS243A is characterized for operation from 0°C to 70°C.
FUNCTION TABLE
INPUTS
FUNCTION
OEAB
OEBA
L
L
H
H
B to A
H
L
Isolation
L
H
Latch A and B
(A = B)
A to B
Copyright 1994, 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.
• DALLAS, TEXAS 75265
• HOUSTON, TEXAS 77251−1443
POST OFFICE BOX 655303
POST OFFICE BOX 1443
1
