SN54ALS138A
SN54ALS138A is 3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS manufactured by Texas Instruments.
description
The ′ALS138A and ′AS138 are 3-line to 8-line decoders/demultiplexers designed for highperformance memory-decoding or data-routing applications requiring very short propagation delay times. In high-performance systems, these devices can be used to minimize the effects of system decoding. When employed with high-speed memories with a fast enable circuit, the delay times of the decoder and the enable time of the memory are usually less than the typical access time of the memory. The effective system delay introduced by the Schottky-clamped system decoder is negligible.
SN54ALS138A, SN54AS138 . . . J PACKAGE SN74ALS138A, SN74AS138 . . . D OR N PACKAGE
(TOP VIEW)
A1 B2 C3 G2A 4 G2B 5 G1 6 Y7 7 GND 8
16 VCC 15 Y0 14 Y1 13 Y2 12 Y3 11 Y4 10 Y5 9 Y6
SN54ALS138A, SN54AS138 . . . FK PACKAGE (TOP VIEW)
Y0
C G2A
NC G2B
G1
3 2 1 20 19
18 Y1
17 Y2
16 NC
15 Y3
14 Y4
9 10 11 12 13
Y5
Y6
Y7
The conditions at the binary-select (A, B, and C) inputs and the three enable (G1, G2A, and G2B) inputs select one of eight output lines. Two
- No internal connection 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.
The SN54ALS138A and SN54AS138 are characterized for operation over the full military temperature range of
- 55°C to 125°C. The SN74ALS138A and SN74AS138 are characterized for operation from 0°C to 70°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...
