54LS74 DM54LS74A DM74LS74A Dual Positive-Edge-Triggered
D Flip-Flops with Preset Clear and Complementary Outputs
June 1989
54LS74 DM54LS74A 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 informa-
tion on the D input is accepted by the flip-flops on the posi-
tive 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
Features
Y
Alternate military aerospace device (54LS74) is avail-
able Contact a National Semiconductor Sales Office
Distributor for specifications
Connection Diagram
Dual-In-Line Package
TL F 6373 – 1
Order Number 54LS74DMQB 54LS74FMQB 54LS74LMQB
DM54LS74AJ DM54LS74AW DM74LS74AM or DM74LS74AN
See NS Package Number E20A J14A M14A N14A or W14B
Function Table
Inputs
PR
L
H
L
H
H
H
CLR
H
L
L
H
H
H
CLK
X
X
X
D
X
X
X
H
L
X
Outputs
Q
H
L
H
H
L
Q
0
Q
L
H
H
L
H
Q
0
u
u
L
H
e
High Logic Level
X
e
Either Low or High Logic Level
L
e
Low Logic Level
u
e
Positive-going Transition
e
This configuration is nonstable that is it will not persist when either the preset
and or clear inputs return to their inactive (high) level
Q
0
e
The output logic level of Q before the indicated input conditions were established
C
1995 National Semiconductor Corporation
TL F 6373
RRD-B30M105 Printed in U S A
NSC [ NATIONAL SEMICONDUCTOR ]
