DM74LS74A Dual Positive-Edge-Triggered D Flip-Flops with Preset, Clear and Complementary Outputs
August 1986
Revised March 2000
DM74LS74A
Dual Positive-Edge-Triggered D Flip-Flops with
Preset, Clear and Complementary Outputs
General Description
This device contains two independent positive-edge-trig-
gered D flip-flops with complementary outputs. The infor-
mation on the D input is accepted by the flip-flops on the
positive going edge of the clock pulse. The triggering
occurs at a voltage level and is not directly related to the
transition time of the rising edge of the clock. The data on
the D input may be changed while the clock is LOW or
HIGH without affecting the outputs as long as the data
setup and hold times are not violated. A low logic level on
the preset or clear inputs will set or reset the outputs
regardless of the logic levels of the other inputs.
Ordering Code:
Order Number
DM74LS74AM
DM74LS85ASJ
DM74LS74AN
Package Number
M14A
M14D
N14A
Package Description
14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-120, 0.150 Narrow
14-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
Function Table
Inputs
PR
L
H
L
H
H
H
CLR
H
L
L
H
H
H
CLK
X
X
X
↑
↑
L
D
X
X
X
H
L
X
Q
H
L
H
L
Q
0
Outputs
Q
L
H
L
H
Q
0
H (Note 1) H (Note 1)
H
=
HIGH Logic Level
X
=
Either LOW or HIGH Logic Level
L
=
LOW Logic Level
↑ =
Positive-going Transition
Q
0
=
The output logic level of Q before the indicated input conditions were
established.
Note 1:
This configuration is nonstable; that is, it will not persist when either
the preset and/or clear inputs return to their inactive (HIGH) level.
© 2000 Fairchild Semiconductor Corporation
DS006373
www.fairchildsemi.com
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