SN54AHC138, SN74AHC138
3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS
SCLS258J 鈥?DECEMBER 1995 鈥?REVISED FEBRUARY 2002
D
D
D
D
D
Operating Range 2-V to 5.5-V V
CC
Designed Specifically for High-Speed
Memory Decoders and Data-Transmission
Systems
Incorporate Three Enable Inputs to Simplify
Cascading and/or Data Reception
Latch-Up Performance Exceeds 250 mA Per
JESD 17
ESD Protection Exceeds JESD 22
鈥?2000-V Human-Body Model (A114-A)
鈥?200-V Machine Model (A115-A)
鈥?1000-V Charged-Device Model (C101)
SN54AHC138 . . . J OR W PACKAGE
SN74AHC138 . . . D, DB, DGV, N, NS, OR PW PACKAGE
(TOP VIEW)
A
B
C
G2A
G2B
G1
Y7
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
Y0
Y1
Y2
Y3
Y4
Y5
Y6
description
The 鈥橝HC138 decoders/demultiplexers are
designed for high-performance memory-decoding
and data-routing applications that require 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.
SN54AHC138 . . . FK PACKAGE
(TOP VIEW)
B
A
NC
V
CC
Y0
C
G2A
NC
G2B
G1
4
5
6
7
8
3 2 1 20 19
18
17
16
15
14
9 10 11 12 13
Y1
Y2
NC
Y3
Y4
NC 鈥?No internal connection
The conditions at the binary-select inputs and 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.
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.
Copyright
錚?/div>
2002, Texas Instruments Incorporated
On products compliant to MIL-PRF-38535, all parameters are tested
unless otherwise noted. On all other products, production
processing does not necessarily include testing of all parameters.
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
鈥?/div>
DALLAS, TEXAS 75265
Y7
GND
NC
Y6
Y5
1
1
2
3
4
5
6
7
8
9
