SN54ALS139, SN74ALS139

DUAL 2-LINE TO 4-LINE DECODERS/DEMULTIPLEXERS

SDAS204A – APRIL 1982 – REVISED DECEMBER 1994

Copyright

1

POST OFFICE BOX 655303

Memory Decoders and Data Transmission

Systems

Cascading and /or Data Reception

Small-Outline (D) Packages, Ceramic Chip

Carriers (FK), and Standard Plastic (N) and

Ceramic (J) 300-mil DIPs

description

The

′ALS139 are dual 2-line to 4-line

decoders/demultiplexers designed for use in

high-performance memory-decoding or data-

routing

applications

requiring

very

short

propagation delay times. In high-performance

memory systems, these devices can 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. Therefore,

the effective system delay introduced by the

Schottky-clamped system decoder is negligible.

The

′ALS139 comprise two individual 2-line to

4-line decoders in a single package. The

active-low enable (G) input can be used as a data

line

in

demultiplexing

applications.

These

decoders/demultiplexers feature fully buffered inputs, each of which represents only one normalized load to its

driving circuit. All inputs are clamped with high-performance Schottky diodes to suppress line ringing and

simplify system design.

The SN54ALS139 is characterized for operation over the full military temperature range of – 55

°C to 125°C. The

SN74ALS139 is characterized for operation from 0

°C to 70°C.

FUNCTION TABLE

INPUTS

OUTPUTS

ENABLE

SELECT

OUTPUTS

ENABLE

G

B

A

Y0

Y1

Y2

Y3

H

X

X

H

H

H

H

L

L

LL

HH

H

L

L

HH

LH

H

L

H

LH

HLH

L

H

H

H

H

H

L

SN54ALS139 ...J PACKAGE

SN74ALS139 ...D OR N PACKAGE

(TOP VIEW)

3

2

1 20 19

910 11 12 13

4

5

6

7

8

18

17

16

15

14

2A

2B

NC

2Y0

2Y1

1B

1Y0

NC

1Y1

1Y2

SN54ALS139 . . . FK PACKAGE

(TOP VIEW)

NC – No internal connection

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

1G

1A

1B

1Y0

1Y1

1Y2

1Y3

GND

2G

2A

2B

2Y0

2Y1

2Y2

2Y3

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.