4-bit D-type Register (with 3-state Outputs)
The four D type Flip-Flops operate synchronously from a common clock. The 3-state outputs allow the
device to be used in bus organized systems. The outputs are placed in the 3-stage mode when either of the
output disable pins are in the logic high level.
The input disable allows the flip-flops to remain in their present states without having to disrupt the clock.
If either of the 2 input disables are taken to a logic high level, the Q outputs are fed back to the inputs,
forcing the flip-flops to remain in the same state. Clearing is enabled by taking the clear input to a logic
high level. The data outputs change state on the positive going edge of the clock.
• High Speed Operation: tpd (Clock to Q) = 14 ns typ (CL = 50 pF)
• High Output Current: Fanout of 10 LSTTL Loads
• Wide Operating Voltage: VCC = 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C)
HX X X X L
L L X X X Q0
L H X X Q0
L X H X Q0
L LL L L
L LL HH
Note: When either M or N (or both) is (are) high the output is disabled to the high-impedance state;
however sequential operation of the flip-flops is not affected.