SN74LS221 PDF File ( Datasheet )

DUAL MONOSTABLE MULTIVIBRATORS WITH SCHMITT-TRIGGER INPUTS Each multivibrator of the LS221 features a negative-transition-triggered input and a positive-transition-triggered input either of which can be used as an inhibit input. Pulse triggering occurs at a voltage level and is not related to the transition time of the input pulse. Schmitt-trigger input circuitry for B input allows jitter-free triggering for inputs as slow as 1 volt, second, providing the circuit with excellent noise immunity.