HD74LS74A

Rev.3.00, Jul.22.2005, page 2 of 7

Function Table

Input

Output

Preset

Clear

Clock

D

Q

Q

L

H

X

X

H

L

H

L

X

X

L

H

L

L

X

X

H*

H*

H

H

↑

H

H

L

H

H

↑

L

L

H

H

H

L

X

Q

0

H; high level, L; low level, X; irrelevant,

↑; transition from low to high level,

Q

*;This configuration is nonstable, that is, it will not persist when preset and clear inputs return to their inactive (high) level.

Absolute Maximum Ratings

Item

Symbol

Ratings

Unit

Supply voltage

7

V

Input voltage

7

V

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

—

—

–400

µA

Output current

—

—

8

mA

Operating temperature

Topr

–20

25

75

°C

Clock frequency

0

—

25

MHz

Clock High

25

—

—

Pulse width

Clear Preset

25

—

—

ns

“H” Data

20

↑

—

—

Setup time

“L” Data

20

↑

—

—

ns

Hold time

5

↑

—

—

ns

Note:

↑; The arrow indicates the rising edge.