Texas Instruments JM38510-65802BFA, JM38510-65802BEA, JM38510-65802B2A, SN54HC138J, SN74HC138D Datasheet
...
SN54HC138, SN74HC138
3-LINE TO 8-LINE DECODERS/DEMUL TIPLEXERS
SCLS107C – DECEMBER 1982 – REVISED MA Y 1997
D
Designed Specifically for High-Speed
Memory Decoders and Data Transmission
Systems
D
Incorporate Three Enable Inputs to Simplify
Cascading and/or Data Reception
D
Package Options Include Plastic
Small-Outline (D), Thin Shrink
Small-Outline (PW), and Ceramic Flat (W)
Packages, Ceramic Chip Carriers (FK), and
Standard Plastic (N) and Ceramic (J)
300-mil DIPs
description
The ’HC138 are designed to be used in
high-performance memory-decoding or datarouting applications requiring very short
propagation delay times. In high-performance
memory systems, these decoders can be used to
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. This means that the effective system
delay introduced by the decoders is negligible.
The conditions at the binary-select inputs at the
three enable inputs select one of eight output
lines. Two active-low and one active-high 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.
SN54HC138 ...J OR W PACKAGE
SN74HC138 . . . D, N, OR PW PACKAGE
SN54HC138 ...FK PACKAGE
C
G
2A
NC
G
2B
G1
NC – No internal connection
(TOP VIEW)
A
1
B
2
C
3
2A
G
4
5
G
2B
6
G1
7
Y7
GND
8
(TOP VIEW)
BANC
3212019
4
5
6
7
8
910111213
Y7
GND
NC
16
15
14
13
12
11
10
9
CC
V
Y6
V
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y0
18
17
16
15
14
Y5
CC
Y1
Y2
NC
Y3
Y4
The SN54HC138 is characterized for operation over the full military temperature range of –55°C to 125°C. The
SN74HC138 is characterized for operation from –40°C to 85°C.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
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 1997, Texas Instruments Incorporated
1
SN54HC138, SN74HC138
OUTPUTS
3-LINE TO 8-LINE DECODERS/DEMUL TIPLEXERS
SCLS107C – DECEMBER 1982 – REVISED MA Y 1997
FUNCTION TABLE
INPUTS
ENABLE SELECT
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 XHXXXHHHHHHHH
L XXXXXHHHHHHHH
H LLLLLLHHHHHHH
H LLLLHHLHHHHHH
H LLLHLHHLHHHHH
H LLLHHHHHLHHHH
H LLHLLHHHHLHHH
H LLHLHHHHHHLHH
H LLHHLHHHHHHLH
H L L H H H H H H H H H H L
EN
†
15
0
1
2
3
4
5
6
7
14
13
12
11
10
Y0
Y1
Y2
Y3
Y4
Y5
9
Y6
7
Y7
A
B
C
G1
G2A
2B
G
1
2
3
6
4
5
logic symbols (alternatives)
1
A
2
B
3
C
6
G1
4
G2A
5
2B
G
†
These symbols are in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the D, J, N, PW, and W packages.
BIN/OCT
1
2
4
&
DMUX
0
0
G
7
2
&
0
1
2
3
4
5
6
7
15
14
13
12
11
10
Y0
Y1
Y2
Y3
Y4
Y5
9
Y6
7
Y7
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Loading...