74HC423

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© NXP Semiconductors N.V. 2016. All rights reserved.

Product data sheet

Rev. 7 — 11 February 2016

13 of 19

NXP Semiconductors

74HC423

Dual retriggerable monostable multivibrator with reset

12.3 Power-down considerations

A large capacitor CEXT may cause problems when powering-down the monostable due to

the capacitor’s stored energy. When a system containing this device is powered-down or a

rapid decrease of VCC to zero occurs, the monostable may sustain damage, due to the

capacitor discharging through the input protection diodes. To avoid this possibility, use a

damping diode DEXT preferably a germanium or Schottky type diode able to withstand

large current surges and connect as shown in Figure 15.

Fig 14. Power-up output pulse elimination circuit

Fig 15. Power-down protection circuit