SN54AHCT257, SN74AHCT257
QUADRUPLE 2-LINE TO 1-LINE DATA SELECTORS/MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCLS351E – MAY 1996 – REVISED OCTOBER 1998
SN54AHCT257 . . . J OR W PACKAGE
SN74AHCT257 . . . D, DB, DGV, N, OR PW PACKAGE
(TOP VIEW)
Inputs Are TTL-Voltage Compatible
EPIC (Enhanced-Performance Implanted
CMOS) Process
A/B
1A
V
CC
1
2
3
4
5
6
7
8
16
15
14
13
Package Options Include Plastic
Small-Outline (D), Shrink Small-Outline
(DB), Thin Very Small-Outline (DGV), Thin
Shrink Small-Outline (PW), and Ceramic
Flat (W) Packages, Ceramic Chip Carriers
(FK), and Standard Plastic (N) and Ceramic
(J) DIPs
OE
4A
4B
1B
1Y
2A
12 4Y
11
10
9
2B
3A
3B
3Y
2Y
GND
description
These quadruple 2-line to 1-line data
selectors/multiplexers are designed for 4.5-V to
SN54AHCT257 . . . FK PACKAGE
(TOP VIEW)
5.5-V V
operation.
CC
The ’AHCT257 devices are designed to multiplex
signals from 4-bit data sources to 4-output data
lines in bus-organized systems. The 3-state
outputs do not load the data lines when the
output-enable (OE) input is at the high logic level.
3
2
1 20 19
18
4A
1B
1Y
NC
2A
2B
4
5
6
7
8
17 4B
16
NC
15
4Y
To ensure the high-impedance state during power
14
3A
up or power down, OE should be tied to V
CC
9 10 11 12 13
through a pullup resistor; the minimum value of
the resistor is determined by the current-sinking
capability of the driver.
NC – No internal connection
The SN54AHCT257 is characterized for
operation over the full military temperature range
of –55°C to 125°C. The SN74AHCT257 is
characterized for operation from –40°C to 85°C.
FUNCTION TABLE
INPUTS
OUTPUT
Y
A/B
A
X
L
B
X
X
X
L
OE
H
L
X
L
Z
L
L
L
H
X
X
H
L
L
H
H
L
H
H
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 is a trademark of Texas Instruments Incorporated.
Copyright 1998, Texas Instruments Incorporated
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.
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