74HCSLASHHCT4538 datasheet(11/13 Pages) PHILIPS

Part #	74HC/HCT4538

Description	Dual retriggerable precision monostable multivibrator

PDF	13 Pages

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Manufacturer	PHILIPS [NXP Semiconductors]

Direct Link	http://www.nxp.com

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11 / 13 page

September 1993

Philips Semiconductors

Product speciﬁcation

Dual retriggerable precision monostable

multivibrator

74HC/HCT4538

Fig.11 Power-down protection circuit.

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 sustain 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.11.

Fig.12 Typical pulse width accuracy versus external capacitance; VCC = 4.5 V; Tamb = 25 °C.

Fig.13 Typical pulse width accuracy versus external resistance; VCC = 4.5 V; Tamb = 25 °C.

74HC/HCT4538 Datasheet(PDF) 11 Page - NXP Semiconductors