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Negative voltage to PSoC pin | Cypress Semiconductor

Negative voltage to PSoC pin

Summary: 4 Replies, Latest post by PSoC Rocks on 13 Oct 2012 06:51 AM PDT
Verified Answers: 0
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user_228878049's picture
152 posts

 What happens when a negative voltage drives the input pin of PSoC? Is it gonne bias the internal transistors which may lead to malfunctioning or is there a breakdown somewhere?

And also is there any method wherein I acn generate a -ve voltage using PSoC?

user_1377889's picture
9301 posts

The absolute maximum ratings state that the input to ANY pin may not be less than -0.5V relative to Vss. That implies when you apply a more negative voltage you'll destroy something. For sure!

When there is an AC signal to input to a PSoC you ought to use a level shifter.




user_14586677's picture
7646 posts

A negative voltage to a cmos pin can trigger an internal parasitic SCR which

shorts Vdd to Vss and generally will blow out the supply die internal bond wire.


You can generate a negative voltage using a PWM or Square wave to a pin followed

by a diode multiplier, see

and and


Regards, Dana.



PSoC Rocks's picture
141 posts

 Refer to this blog post - This is applicable to any single voltage sourced chip.




user_14586677's picture
7646 posts

If you need to level shift a signal into CM range of an input, here is a simple

method using just 2 R's -


Regards, Dana,

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