SN54F257, SN74F257

QUADRUPLE 2LINE TO 1LINE DATA SELECTORS/MULTIPLEXERS

WITH 3STATE OUTPUTS

SDFS065A − D2932, MARCH 1987 − REVISED OCTOBER 1993

Copyright

2−1

POST OFFICE BOX 655303

POST OFFICE BOX 1443

System Bus

Sources in High-Performance Systems

Small-Outline Packages, Ceramic Chip

Carriers, and Standard Plastic and Ceramic

300-mil DIPs

description

The

′F257 is designed to multiplex signals from

4-bit data sources to 4-output data lines in

bus-organized systems. The 3-state outputs will

not load the data lines when the output enable

(OE) input is at a high logic level.

The SN54F257 is characterized for operation over

the full military temperature range of − 55

°C to

125

°C. The SN74F257 is characterized for

operation from 0

°C to 70°C.

FUNCTION TABLE

INPUTS

OUTPUT

OE

A /B

A

B

OUTPUT

Y

H

X

X

X

Z

L

LL

X

L

L

LH

X

H

L

HX

L

L

L

H

X

H

H

OE

MUX

2

1A

1

3

1B

EN

15

G1

1

1Y

4

5

2A

6

2B

2Y

7

11

3A

10

3B

3Y

9

14

4A

13

4B

4Y

12

A /B

1

† This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.

Pin numbers shown are for the D, J, and N packages.

SN54F257 ...J PACKAGE

SN74F257 ...D OR N PACKAGE

(TOP VIEW)

32

1 20 19

910 11 12 13

4

5

6

7

8

18

17

16

15

14

4A

4B

NC

4Y

3A

1B

1Y

NC

2A

2B

SN54F257 . . . 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

1A

1B

1Y

2A

2B

2Y

GND

OE

4A

4B

4Y

3A

3B

3Y

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.