The Texas Instruments (TI) SN54/74LS123 dual retriggerable monostable multivibrator is a one-shot device capable of very
long output pulses and up to 100% duty cycle. The ?LS123 also features dc triggering from gated low-level active A and
high-level active B inputs and provides a clear input that terminates the output pulse of any predetermined time independent
of timing components, R ext and C ext . The output pulse duration can also be extended by retriggering the input prior to the
termination of an existing output pulse. Retrigger pulses starting before 0.22 C ext (in pF) ns after the initial trigger pulse will
be ignored and the output duration will remain unchanged.
The B input on an ?LS123 is designed to handle pulses with a transition rate as slow as 0.1 mV/ns, (Schmitt-trigger input) with
jitter-free one-shot action. This capability allows the ?LS123 to be used as an interface element between circuits with very
slow-rising output pulses and circuits that require fast-rising input pulses.