SN54ALS251, SN74ALS251

1-OF-8 DATA SELECTORS/MULTIPLEXERS

WITH 3-STATE OUTPUTS

SDAS215A – APRIL 1982 – REVISED DECEMBER 1994

Copyright

1

POST OFFICE BOX 655303

System Bus

Inverted Data

Small-Outline (D) Packages, Ceramic Chip

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

Ceramic (J) 300-mil DIPs

description

These data selectors/multiplexers contain full

binary decoding to select one-of-eight data

sources and feature controlled complementary

3-state outputs.

The 3-state outputs can interface with and drive

data lines of bus-organized systems. With all but

one of the common outputs disabled (at the

high-impedance state), the low impedance of the

signal-enabled output drives the bus line to a high

or low logic level. Both outputs are controlled by

the output-enable (OE) input. The outputs are

disabled when OE is high.

The SN54ALS251 is characterized for operation

over the full military temperature range of – 55

°C

to 125

°C. The SN74ALS251 is characterized for

operation from 0

°C to 70°C.

FUNCTION TABLE

INPUTS

OUTPUTS

SELECT

OE

OUTPUTS

C

B

A

OE

Y

W

X

X

X

H

Z

Z

L

LL

L

D0

D0

L

LHL

D1

D1

L

HL

L

D2

D2

L

HH

L

D3

D3

H

LL

L

D4

D4

H

LHL

D5

D5

H

HL

L

D6

D6

H

H

H

L

D7

D7

D0, D1, . . . D7 = the level of the respective D input

SN54ALS251 ...J PACKAGE

SN74ALS251 ...D OR N PACKAGE

(TOP VIEW)

32

1 20 19

910 11 12 13

4

5

6

7

8

18

17

16

15

14

D5

D6

NC

D7

A

D1

D0

NC

Y

W

SN54ALS251 . . . FK PACKAGE

(TOP VIEW)

NC – No internal connection

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

D3

D2

D1

D0

Y

W

OE

GND

D4

D5

D6

D7

A

B

C

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.