74HC423N datasheet(10/14 Pages) PHILIPS

10 / 14 page

1998 Jul 08

Philips Semiconductors

Product speciﬁcation

Dual retriggerable monostable

multivibrator with reset

74HC/HCT423

APPLICATION INFORMATION

Power-up considerations

When the monostable is powered-up it may produce an output pulse, with a pulse width defined by the values of RX and

CX, this output pulse can be eliminated using the circuit shown in Fig.11.

Power-down considerations

A large capacitor (CX) may cause problems when powering-down the monostable due to the energy stored in this

capacitor. When a system containing this device is powered-down or a rapid decrease of VCC to zero occurs, the

monostable may substain damage, due to the capacitor discharging through the input protection diodes. To avoid this

possibility, use a damping diode (DX) preferably a germanium or Schottky-type diode able to withstand large current

surges and connect as shown in Fig.12.

Fig.11 Power-up output pulse elimination circuit.

Fig.12 Power-down protection circuit.

74HC423N Datasheet(PDF) 10 Page - NXP Semiconductors