74139 View Datasheet(PDF) - ON Semiconductor
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74139 Datasheet PDF : 8 Pages
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SN74LS139
LOGIC DIAGRAM
Ea
1
A0a A1a
2
3
Eb
15
A0b A1b
14
13
VCC = PIN 16
GND = PIN 8
= PIN NUMBERS
4
5
6
O0a O1a O2a
7
12
11
10
9
O3a O0b O1b O2b O3b
FUNCTIONAL DESCRIPTION
The LS139 is a high speed dual 1-of-4 decoder/
demultiplexer fabricated with the Schottky barrier diode
process. The device has two independent decoders, each of
which accept two binary weighted inputs (A0, A1) and
provide four mutually exclusive active LOW outputs
(O0–O3). Each decoder has an active LOW Enable (E).
When E is HIGH all outputs are forced HIGH. The enable
can be used as the data input for a 4-output demultiplexer
application.
Each half of the LS139 generates all four minterms of two
variables. These four minterms are useful in some
applications, replacing multiple gate functions as shown in
Fig. a, and thereby reducing the number of packages
required in a logic network.
TRUTH TABLE
INPUTS
OUTPUTS
E A0 A1 O0 O1 O2 O3
H
X
X
H
H
H
H
L
L
L
L
H
H
H
L
H
L
H
L
H
H
L
L
H
H
H
L
H
L
H
H
H
H
H
L
H = HIGH Voltage Level
L = LOW Voltage Level
X = Don’t Care
E
E
A0
O0 A0
O0
A1
A1
E
E
A0
O1 A0
O1
A1
A1
E
E
A0
O2 A0
O2
A1
A1
E
E
A0
O3 A0
O3
A1
A1
Figure a
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