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HD74LS221
Dual Monostable Multivibrators
REJ03D0458–0300 Rev.3.00
Jul.15.2005
This multivibrator 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 particular voltage level and is not directly related to the transition time of the input pulse. Schmitt-trigger input circuitry (TTL hysteresis) for B input allows jitter-free triggering from inputs with transition rates as slow as 1 V/s, providing the circuit with excellent noise immunity of typically 1.2 V. A high immunity to VCC noise of typically 1.5 V is also provided by internal latching circuitry.