HD74LS257

Rev.3.00, Jul.15.2005, page 2 of 5

Function Table

Inputs

OC

S

A

B

Output

H

X

X

X

Z

L

L

L

X

L

L

L

H

X

H

L

H

X

L

L

L

H

X

H

H

Note:

H; high level, L; low level, X; irrelevant, Z; off (high-impedance) state of a 3-state output

Block Diagram

S

Output

Control

1A

1Y

4Y

3Y

2Y

1B

2A

2B

3A

3B

4A

4B

Absolute Maximum Ratings

Item

Symbol

Ratings

Unit

Supply voltage

7

V

Input voltage

7

V

Output voltage (off-state)

5.5

V

Operating temperature

Topr

–20 to +75

°C

Power dissipation

400

mW

Storage temperature

Tstg

–65 to +150

°C

Note:

Voltage value, unless otherwise noted, are with respect to network ground terminal.

Recommended Operating Conditions

Item

Symbol

Min

Typ

Max

Unit

Supply voltage

4.75

5.00

5.25

V

—

—

–2.6

mA

Output current

—

—

8

mA

Operating temperature

Topr

–20

25

75

°C