TEXAS INSTRUMENTS CD74HCT4538E

The CD74HCT4538E is a dual retriggerable/resettable monostable Precision Multivibrator for fixed voltage timing applications. An external resistor (RX) and an external capacitor (CX) control the timing and the accuracy for the circuit. Adjustment of RX and CX provides a wide range of output pulse widths from the Q and Q\ terminals. The propagation delay from trigger input-to-output transition and the propagation delay from RESET input-to-output transition are independent of RX and CX. Leading-edge triggering (A) and trailing edge triggering (B)\ inputs are provided for triggering from either edge of the input pulse. An unused A input should be tied to GND and an unused B\ should be tied to VCC. On power up the IC is RESET. Unused resets and sections must be terminated. In normal operation the circuit retriggers on the application of each new trigger pulse. To operate in the non-triggerable mode Q\ is connected to B\.