Consequences of supply voltage problems - e.g.  MC68HC908JW32

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Consequences of supply voltage problems - e.g.  MC68HC908JW32

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andym8
Contributor I

Hi, What are likely symptoms and issues seen when a MCU, eg. MC68HC908JW32, receive large voltage spike / over voltage.

 

Many Thanks.

 

 

 

 

 

 

 

Added p/n to subject.

Message Edited by NLFSJ on 2009-04-07 10:06 AM
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peg
Senior Contributor IV

Hello and welcome to the fora, Andy

 

In my experience the first abnormal behaviour that occurs with excessive noise - spikes on the power supply is unexpected transitions being recorded on i/o pins. This is especially noticable on pins that generate interrupts.

 

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andym8
Contributor I

Thanks for the insight. What about possible permanent damage?

At what sort of levels could damage be done, is it possible to 'burn the chip out' through overheating maybe?

Many Thanks for your time.

 

I will check when I return to work, but I believe quick basic tests had showed supply V+ was now directly connected to D+. I presume this is not desirable. MCU was still incircuit so problems could be elsewhere.

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peg
Senior Contributor IV

Of course, exceeding the absolute max voltage specs with a solid power supply for any  length of time will generally destroy the chip. Sometimes you can be lucky and it still works, but it will more than likely be prone to failure later.

 

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