SNJ54HCT138J Datasheet, PDF (2/21 Pages) Texas Instruments – 3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS

SN54HCT138, SN74HCT138
3ĆLINE TO 8ĆLINE DECODERS/DEMULTIPLEXERS
SCLS171E − MARCH 1984 − REVISED SEPTEMBER 2003
description/ordering information (continued)
The conditions at the binary-select inputs and the three enable inputs select one of eight output lines. Two
active-low (G) and one active-high (G) enable inputs reduce the need for external gates or inverters when
expanding. A 24-line decoder can be implemented without external inverters, and a 32-line decoder requires
only one inverter. An enable input can be used as a data input for demultiplexing applications.
FUNCTION TABLE
ENABLE
INPUTS
SELECT
OUTPUTS
G1 G2A G2B C
B
A
Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7
X
H
X
X
X
X
H
H
H
H
H
H
H
H
X
X
H
X
X
X
H
H
H
H
H
H
H
H
L
X
X
X
X
X
H
H
H
H
H
H
H
H
H
L
L
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
L
H
H
L
H
H
H
H
H
H
H
L
L
L
H
L
H
H
L
H
H
H
H
H
H
L
L
L
H
H
H
H
H
L
H
H
H
H
H
L
L
H
L
L
H
H
H
H
L
H
H
H
H
L
L
H
L
H
H
H
H
H
H
L
H
H
H
L
L
H
H
L
H
H
H
H
H
H
L
H
H
L
L
H
H
H
H
H
H
H
H
H
H
L
2
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