HCF4538 datasheet(8/14 Pages) STMICROELECTRONICS

部品番号	HCF4538

部品情報	DUAL MONOSTABLE MULTIVIBRATOR

PDF	14 Pages

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メーカー	STMICROELECTRONICS [STMicroelectronics]

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8 / 14 page

Power Down Mode

During a rapid power-down conditiona, as would

occur with a power supply short circuit or with a

poorly filtered power supply, the energy stored in CX

could discharge into Pin 2 or 14. To Avoid possible

device damage in this mode, when CX is

≤0.5micro-

farad, a aprotection diode with a 1 Ampere or higher

rating (1N5395 or equivalent) and a separate

ground return for CX should be provided as shown

in Fig. 1

An alternate protection method is shown in Fig. 2,

where a 51

Ω current limit resistor is inserted in

series with CX. Note that a small pulse width de-

crease will occour however, and RX must be appro-

priately increased to obtain the originally desired

pulse width.

Figure 1: rapid Power Down Protection Circuit

Figure 2: Alternate rapid Power Down Protection

Circuit

HCC/HCF4538B

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HCF4538 データシート(PDF) 8 Page - STMicroelectronics