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Date: Wed, 26 Feb 2020 13:46:20 -0800
Subject: Re: [EE] 74LVC1G332 input clamping current only specified for VI <
 0 V
Thread-Topic: [EE] 74LVC1G332 input clamping current only specified for VI <
 0 V
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Quoting Jason White <whitewaterssoftwareinfo@gmail.com>:

> Hello,
>
> I am considering subjecting the input of a 74LVC1G332 to 12 to 48V
> though a resistor and relying upon the internal clamping diodes.
>
> Problem is, this device only specifies clamping diode current for VI <
> 0 V (and not for VI > VCC). However, it does specify that it passes
> various EMI certifications.
>
> I know I could use an Zener diode, but I am curious: what is going on
> here with the datasheet specification?
>

Hi, Jason: -

That's a 5V-tolerant part, so does not have a clamping network to Vcc.
There's no doubt some kind of zener like structure inside for ESD.

It's not the best to rely on the diodes during normal operation as
they can result in excessive current draw or other strange behavior.
A BAT54S dual Schottky will clamp to both rails before any diode in the
gate gets a chance to conduct much. The clamping numbers are abs max.

Best regards,
Spehro Pefhany

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