HD74HC221
Dual Monostable Multivibrators (with Schmitt Trigger Input)
Description
Each multivibrator features both a negative, A, and a positive, B, transition triggered input, either of which
can be used as an inhibit. Also included is a clear inpt that when taken low resets the one shot. The
HD74HC221 can be triggered on the positive transition of teh clear while A is held low and B is held high.
This device is a non-retriggerable, and therefore cannot be retriggered until the output pulse times out.
The output pulse equation is simply:
t
W
= 0.7·(Rext)·(Cext)
Features
• High Speed Operation
• High Output Current: Fanout of 10 LSTTL Loads
• Wide Operating Voltage: V
CC
= 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current
Function Table
Inputs Outputs
Clear A B Q Q
LXXLH
XH
XX L L H
HL
H H
LH