The SN74121N is a monostable Multi-vibrator with Schmitt-trigger inputs features dual negative-transition-triggered inputs and a single positive-transition-triggered input which can be used as an inhibit input. Complementary output pulses are provided. 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 the B-input allow jitter-free triggering from inputs with transition rates as slow as 1 volt/second, providing the circuit with an excellent noise immunity of typically 1.2V. A high immunity to VCC noise of typically 1.5V is also provided by internal latching circuitry. Input pulses may be of any duration relative to the output pulse. Output rise and fall times are TTL compatible and independent of pulse length. Pulse width stability is achieved through internal compensation and is virtually independent of VCC and temperature.