
SCLS107E DECEMBER 1982 REVISED SEPTEMBER 2003
1
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
Targeted Specifically for High-Speed
Memory Decoders and Data-Transmission
Systems
Wide Operating Voltage Range of 2 V to 6 V
Outputs Can Drive Up To 10 LSTTL Loads
Low Power Consumption, 80-
μ
A Max I
CC
Typical t
pd
= 15 ns
±
4-mA Output Drive at 5 V
Low Input Current of 1
μ
A Max
Incorporate Three Enable Inputs to Simplify
Cascading and/or Data Reception
description/ordering information
The ’HC138 devices are designed to be used in
high-performance memory-decoding or data-
routing
applications
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.
requiring
very
short
ORDERING INFORMATION
TA
PACKAGE
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
PDIP N
Tube of 25
SN74HC138N
SN74HC138N
Tube of 40
SN74HC138D
SOIC D
Reel of 2500
SN74HC138DR
HC138
Reel of 250
SN74HC138DT
40 C to 85 C
SOP NS
Reel of 2000
SN74HC138NSR
HC138
SSOP DB
Reel of 2000
SN74HC138DBR
HC138
Tube of 90
SN74HC138PW
TSSOP PW
Reel of 2000
SN74HC138PWR
HC138
Reel of 250
SN74HC138PWT
CDIP J
Tube of 25
SNJ54HC138J
SNJ54HC138J
55 C to 125 C
CFP W
Tube of 150
SNJ54HC138W
SNJ54HC138W
LCCC FK
Tube of 55
SNJ54HC138FK
SNJ54HC138FK
Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are
available at www.ti.com/sc/package.
3
2 1 20 19
9 10 11 12 13
4
5
6
7
8
18
17
16
15
14
Y1
Y2
NC
Y3
Y4
C
G2A
NC
G2B
G1
B
A
N
Y
Y
V
Y
Y
G
N
SN54HC138 . . . FK PACKAGE
(TOP VIEW)
NC No internal connection
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
A
B
C
G2A
G2B
G1
Y7
GND
V
CC
Y0
Y1
Y2
Y3
Y4
Y5
Y6
SN54HC138 . . . J OR W PACKAGE
SN74HC138 . . . D, DB, N, NS, OR PW PACKAGE
(TOP VIEW)
Copyright
2003, Texas Instruments Incorporated
'*%$"# $')!"
" 1
%)# ",&.#&
"&*+
!)) ",& '*%$"#
'$#0
* "
&$#!)/
$)%*& ""0
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.
!"
# $%&"
'& ",& "
'$#0
!#
'%()$!"
&-!# #"%&"#
&$#!)/
*!"&+
*%$"#
#"!*!* .!!"/+
""0
$
" #'&$$!"#
*%$"
* "
$)%*&
!)) '!!&"+
!)) '!!&"
!& ""&*
'*%$"
!)) '!!&"+