74LV423

NOTES:
1. Stresses beyond those listed may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
2. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.

The 74LV423 is a low-voltage Si-gate CMOS device and is pin and function compatible with the 74HC/HCT423.

The 74LV423 is a dual retriggerable monostable multivibrator with output pulse width control by three methods. The basic pulse time is programmed by selection of an external resistor (R_EXT) and capacitor (C_EXT). They are normally connected as shown in Figure 1. Once triggered, the basic output pulse width may be extended by retriggering the gated active LOW-going edge input (nA) or the active HIGH-going edge input (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, which also inhibits the triggering. Figures 2 and 3 illustrate pulse control by retriggering and early reset. The basic output pulse width of the 74LV423 is essentially determined by the values of the external timing components REXT and CEXT. For pulse width when C_EXT <10000pF,see Figure 6. When C_EXT > 10,000pF, the typical output pulse width is defined as: t_W = 0.45 * R_EXT * C_EXT (typ.), where t_W = pulse width in ns; R_EXT = external resistor in KW; and C_EXT = external capacitor in pF. Schmitt-trigger action in the nA and nB inputs makes the circuit highly tolerant of slower input rise and fall times.