The 74LVC1G123 is a single retriggerable monostable multivibrator with Schmitt trigger inputs. Output pulse width is controlled by three methods:
- The basic pulse is programmed by selection of an external resistor (REXT) and capacitor (CEXT).
- Once triggered, the basic output pulse width may be extended by retriggering the gated active LOW-going edge input (A) or the active HIGH-going edge input (B). By repeating this process, the output pulse period (Q = HIGH) can be made as long as desired. Alternatively an output delay can be terminated at any time by a LOW-going edge on input CLR, which also inhibits the triggering.
- An internal connection from CLR to the input gates makes it possible to trigger the circuit by a HIGH-going signal at input CLR.
Inputs can be driven from either 3.3 V or 5 V devices. This feature allows the use of these devices as translators in a mixed 3.3 V and 5 V environment. Schmitt trigger inputs, makes the circuit highly tolerant to slower input rise and fall times.
This device is fully specified for partial power-down applications using IOFF. The IOFF circuitry disables the output, preventing the damaging backflow current through the device when it is powered down.