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Altera_Forum
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15 years ago

CPLD EPM240T Serious Burn down!!

Hi,I met a very bad problem when I use CPLD EPM240T. (1) Environment : in this project,it have 10 IO board with EPM240T,all these board connected through one back board.Between these EPM240T,t...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

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there is a surge at poweron

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Overvoltage had been also my assumption. Basically, the bad performing power supply should be replaced by something reliable.

It's not easy to limit the supply voltage at the board level. A 3.3V TVS diode won't considerably reduce the overvoltage because it's characteristic is too soft. A thyristor crowbar circuit could act more effectively but needs supply disconnect, if trigerred. And it possibly causes more harm with a badly designed power distribution system.