General Description
The DM74LS221 is a dual monostable multivibrator with
Schmitt-trigger input. Each device has three inputs permitting
the choice of either leading-edge or trailing-edge triggering.
Pin (A) is an active-LOW trigger transition input and
pin (B) is an active-HIGH transition Schmitt-trigger input
that allows jitter free triggering for inputs with transition
rates as slow as 1 volt/second. This provides the input with
excellent noise immunity. Additionally an internal latching
circuit at the input stage also provides a high immunity to
VCC noise. The clear (CLR) input can terminate the output
pulse at a predetermined time independent of the timing
components. This (CLR) input also serves as a trigger
input when it is pulsed with a low level pulse transition
(
). To obtain the best and trouble free operation from
this device please read operating rules as well as the Fairchild
Semiconductor one-shot application notes carefully
and observe recommendations.

Features

A dual, highly stable one-shot

Compensated for VCC and temperature variations

Pin-out identical to DM74LS123 (Note 1)

Output pulse width range from 30 ns to 70 seconds

Hysteresis provided at (B) input for added noise
immunity

Direct reset terminates output pulse

Triggerable from CLEAR input

DTL, TTL compatible

Input clamp diodes