74LV123DB

The 74LV123 is a dual retriggerable monostable multivibrator with reset. The basic output pulse width is programmed by selection of external components (R_EXT and C_EXT). Once triggered this basic pulse width may be extended by retriggering either of the edge triggered inputs (nA or (nB). By repeating this process, the output pulse period (nQ = HIGH, nQ = LOW) can be made as long as desired. Alternatively, an output delay can be terminated at any time by a LOW-going edge on input nRD. Control inputs include clamp diodes. This enables the use of current limiting resistors to interface inputs to voltages in excess V_CC. Schmitt-trigger action at nA and nB inputs makes the circuit tolerant of slower input rise and fall times.