In article ,
Jeff Wisnia wrote:
Ed Angell 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 ??

snipped

I've no hard data, but I sure think it's the way to bet.

The thermal expansion/contraction of repeated on-off cycles, tending to
make something "crack", coupled with the fact that chemical reactions
take place faster at higher temperatures, would make me think that lower
temperatures would make for longer life.

In particular, there are existing cracks in chips resulting from
the dicing process (breaking apart the silicon wafer into all the
individual chips).

If the crack is curved so it points back to the edge -- no
problems. However, if it is pointed towards the active area, then it
will grow with repeated temperature cycling (note that staying warm is
better than shooting up and down frequently). The action is like that of
a crack in your windshield. It may sit there all summer as a nice short
little crack, but once winter comes, and you start blowing heated air on
a frozen windshield, that crack will grow.

One of the things which makes transistors and ICs made to mil
specs so expensive relative to commercial ones is that each chip is
microscopically examined, and those with cracks which are pointing
towards an active area are rejected (perhaps to wind up in commercial
chips with the same basic part number.

Enjoy,
DoN.

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