SEMICONDUCTOR TECHNICAL DATA
High–Performance Silicon–Gate CMOS
The MC54/74HC138A is identical in pinout to the LS138. The device
inputs are compatible with standard CMOS outputs; with pullup resistors,
they are compatible with LSTTL outputs.
The HC138A decodes a three–bit Address to one–of–eight active–low
outputs. This device features three Chip Select inputs, two active–low and
one active–high to facilitate the demultiplexing, cascading, and chip–select-
ing functions. The demultiplexing function is accomplished by using the
Address inputs to select the desired device output; one of the Chip Selects is
used as a data input while the other Chip Selects are held in their active
states.
J SUFFIX
CERAMIC PACKAGE
CASE 620–10
16
16
1
N SUFFIX
PLASTIC PACKAGE
CASE 648–08
1
•
•
•
•
•
•
Output Drive Capability: 10 LSTTL Loads
Outputs Directly Interface to CMOS, NMOS and TTL
Operating Voltage Range: 2.0 to 6.0 V
Low Input Current: 1.0 µA
High Noise Immunity Characteristic of CMOS Devices
In Compliance with the Requirements Defined by JEDEC Standard
No. 7A
D SUFFIX
SOIC PACKAGE
CASE 751B–05
16
1
DT SUFFIX
TSSOP PACKAGE
CASE 948F–01
16
1
•
Chip Complexity: 100 FETs or 29 Equivalent Gates
LOGIC DIAGRAM
ORDERING INFORMATION
MC54HCXXXAJ
MC74HCXXXAN
MC74HCXXXAD
MC74HCXXXADT
Ceramic
Plastic
SOIC
1
2
3
15
A0
A1
A2
Y0
14
13
12
ADDRESS
INPUTS
Y1
Y2
Y3
TSSOP
ACTIVE–LOW
OUTPUTS
11
10
Y4
Y5
Y6
Y7
PIN ASSIGNMENT
9
7
A0
A1
1
2
16
15
14
13
V
CC
Y0
Y1
Y2
6
4
3
4
5
6
A2
CS1
CS2
CHIP–
SELECT
INPUTS
PIN 16 = V
PIN 8 = GND
CC
CS2
5
CS3
CS1
12
11
Y3
Y4
CS3
7
8
10
9
Y7
Y5
Y6
FUNCTION TABLE
GND
Inputs
Outputs
CS1CS2 CS3 A2 A1 A0 Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7
X
X
L
X
H
X
H
X
X
X
X
X
X
X
X
X
X
X
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
H
L
H
L
L
H
H
H
H
L
H
H
H
H
L
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
L
H
H
H
H
L
L
H
H
L
H
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
L
H
H
H
H
L
H
H
H
L
H
H
H = high level (steady state); L = low level (steady state);
X = don’t care
10/95
Motorola, Inc. 1995
REV 6
1