SN54121,SN74121,pdf(MONOSTABLE MULTIVIBRATORS)
These mulTIvibrators feature 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 1.2 volts. A high immunity to VCC noise of typically 1.5 volts is also provided by internal latching circuitry.
Once fired, the outputs are independent of further transitions of the inputs and are a function only of the timing components.
