5-230
FAST AND LS TTL DATA
1-OF-8 DECODER/
DEMULTIPLEXER
The LSTTL/MSI SN54/74LS138 is a high speed 1-of-8 Decoder/
Demultiplexer. This device is ideally suited for high speed bipolar memory
chip select address decoding. The multiple input enables allow parallel ex-
pansion to a 1-of-24 decoder using just three LS138 devices or to a 1-of-32
decoder using four LS138s and one inverter. The LS138 is fabricated with the
Schottky barrier diode process for high speed and is completely compatible
with all Motorola TTL families.
• Demultiplexing Capability
• Multiple Input Enable for Easy Expansion
• Typical Power Dissipation of 32 mW
• Active Low Mutually Exclusive Outputs
• Input Clamp Diodes Limit High Speed Termination Effects
C0049C0052 C0049C0051 C0049C0050 C0049C0049 C0049C0048 C0057
C0049 C0050 C0051 C0052 C0053 C0054 C0055
C0049C0054 C0049C0053
C0056
C0086
C0067C0067
C0065
C0048
C0079
C0048
C0079
C0049
C0079
C0050
C0079
C0051
C0079
C0053
C0079
C0052
C0079
C0054
C0065
C0049
C0065
C0050
C0069
C0049
C0069
C0050
C0069
C0051
C0079
C0055
C0071C0078C0068
CONNECTION DIAGRAM DIP (TOP VIEW)
NOTE:
The Flatpak version
has the same pinouts
(Connection Diagram) as
the Dual In-Line Package.
PIN NAMES LOADING (Note a)
HIGH LOW
A
0
–A
2
E
1
, E
2
E
3
O
0
–O
7
Address Inputs
Enable (Active LOW) Inputs
Enable (Active HIGH) Input
Active LOW Outputs (Note b)
0.5 U.L.
0.5 U.L.
0.5 U.L.
10 U.L.
0.25 U.L.
0.25 U.L.
0.25 U.L.
5 (2.5) U.L.
NOTES:
a) 1 TTL Unit Load (U.L.) = 40 µA HIGH/1.6 mA LOW.
b) The Output LOW drive factor is 2.5 U.L. for Military (54) and 5 U.L. for Commercial (74)
Temperature Ranges.
SN54/74LS138
1-OF-8 DECODER/
DEMULTIPLEXER
LOW POWER SCHOTTKY
J SUFFIX
CERAMIC
CASE 620-09
N SUFFIX
PLASTIC
CASE 648-08
16
1
16
1
ORDERING INFORMATION
SN54LSXXXJ Ceramic
SN74LSXXXN Plastic
SN74LSXXXD SOIC
16
1
D SUFFIX
SOIC
CASE 751B-03
LOGIC SYMBOL
C0086
C0067C0067
C0061 C0080C0073C0078 C0049C0054
C0071C0078C0068 C0061 C0080C0073C0078 C0056
C0049C0053 C0049C0052 C0049C0051 C0049C0050 C0049C0049 C0049C0048 C0057
C0049 C0050 C0051 C0052 C0053 C0054
C0049C0050 C0051
C0065
C0048
C0065
C0049
C0065
C0050
C0069
C0079
C0048
C0079
C0049
C0079
C0050
C0079
C0051
C0079
C0052
C0079
C0053
C0079
C0054
C0079
C0055
C0055
LOGIC DIAGRAM
C0065
C0050
C0065
C0049
C0065
C0048
C0069
C0049
C0069
C0050
C0069
C0051
C0079
C0055
C0079
C0054
C0079
C0053
C0079
C0052
C0079
C0051
C0079
C0050
C0079
C0049
C0079
C0048
C0086
C0067C0067
C0061 C0080C0073C0078 C0049C0054
C0071C0078C0068 C0061 C0080C0073C0078 C0056
C0061 C0080C0073C0078 C0078C0085C0077C0066C0069C0082C0083
C0051 C0050 C0049 C0052 C0053 C0054
C0055 C0057
C0049C0053C0049C0052C0049C0051C0049C0050
C0049C0049C0049C0048