SN54ALS139_08 Datasheet, PDF (1/15 Pages) Texas Instruments – DUAL 2-LINE TO 4-LINE DECODERS/DEMULTIPLEXERS

SN54ALS139, SN74ALS139
DUAL 2-LINE TO 4-LINE DECODERS/DEMULTIPLEXERS
SDAS204A – APRIL 1982 – REVISED DECEMBER 1994
• Designed Specifically for High-Speed
Memory Decoders and Data Transmission
Systems
• Incorporate Two Enable Inputs to Simplify
Cascading and /or Data Reception
• Package Options Include Plastic
Small-Outline (D) Packages, Ceramic Chip
Carriers (FK), and Standard Plastic (N) and
Ceramic (J) 300-mil DIPs
description
The ′ALS139 are dual 2-line to 4-line
decoders/demultiplexers designed for use in
high-performance memory-decoding or data-
routing applications requiring very short
propagation delay times. In high-performance
memory systems, these devices can minimize the
effects of system decoding. When employed with
high-speed memories utilizing a fast-enable
circuit, the delay times of these decoders and the
enable time of the memory are usually less than
the typical access time of the memory. Therefore,
the effective system delay introduced by the
Schottky-clamped system decoder is negligible.
SN54ALS139 . . . J PACKAGE
SN74ALS139 . . . D OR N PACKAGE
(TOP VIEW)
1G 1
1A 2
1B 3
1Y0 4
1Y1 5
1Y2 6
1Y3 7
GND 8
16 V_CC
15 2G
14 2A
13 2B
12 2Y0
11 2Y1
10 2Y2
9 2Y3
SN54ALS139 . . . FK PACKAGE
(TOP VIEW)
3 2 1 20 19
1B 4
18 2A
1Y0 5
17 2B
NC 6
16 NC
1Y1 7
15 2Y0
1Y2 8
14 _2Y1
9 10 11 12 13
The ′ALS139 comprise two individual 2-line to
4-line decoders in a single package. The
active-low enable (G) input can be used as a data
NC – No internal connection
line in demultiplexing applications. These
decoders/demultiplexers feature fully buffered inputs, each of which represents only one normalized load to its
driving circuit. All inputs are clamped with high-performance Schottky diodes to suppress line ringing and
simplify system design.
The SN54ALS139 is characterized for operation over the full military temperature range of – 55°C to 125°C. The
SN74ALS139 is characterized for operation from 0°C to 70°C.
FUNCTION TABLE
INPUTS
ENABLE
G
SELECT
B
A
OUTPUTS
Y0 Y1 Y2 Y3
H
X
X
H
H
H
H
L
L
L
L
H
H
H
L
L
H
H
L
H
H
L
H
L
H
H
L
H
L
H
H
H
H
H
L
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.
• POST OFFICE BOX 655303 DALLAS, TEXAS 75265
Copyright © 1994, Texas Instruments Incorporated
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