On Wed, 9 Feb 2005 08:21:33 -0800, the renowned "Ed Angell"
edangellatcomcastdotnet wrote:

Sorry for the OT post, but I don't know a better group of knowledgeable
folks to ask.

As long as a triac is run within it's published temperature limits, is there
any shortening of their life due to running warm ??

Proabably. Running right at the limits will shorten the life. But
thermal cycling can really kill power semiconductors, especially the
cheap-a** TO-220 type. The bond between die and leadframe/heatsink
fails, causing the semiconductor die itself to overheat. I've seen
failures in the range of xE4 cycles where x is a single digit.

Also, if the die is already very hot, a surge of current that it might
otherwise survive can heat the die enough to destroy it.


Thanks for the time to answer this question.

Ed Angell



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