Lifetime of an SMPS?

[cupoftea]

Pg 14 of this....

https://en.cosel.co.jp/tool/tag/pdf/CME_TU.pdf

....Suggests that lifetime of an SMPS depends mostly on when the solder joints will eventually go dry....and says the eventual dryness gets caused by the frequency of temperature cycling of the SMPS.
I thought internal bonding wires of power FETs and diodes were the things most affected by temperature cycling? (eventually just snapping off) Also, i thought it was film and electrolytic capacitor lifetimes that most impacted overall lifetime?

 

[Easy peasy]

they are correct - soldering ( the long term chemical processes therein ) remains the main limitation for life of electronic equipment

hence the gold eutectics used on the space program for voyager etc - no long term chemical action - stable solder joints with flexibilty ...

cheaper electro's run at too high a rating are a close second ...

--- Updated Jan 9, 2022 ---

in plastic package mosfets / diodes ( TO-2220 / 247 / 268 ) the bond wires are trapped in place by the epoxy - even in metal can - there are no forces to snap off the bond wire,

where did you get this information from ?

 

[cupoftea]

where did you get this information from ?

Thanks, ill try and dig it out. Its probably in my LED drivers folder somewhere, as i remember being told that power LED bonding wires can also snap off after years of thermal cycling....i seem to remember it was in Philips literature, but ill check.

 

[Warpspeed]

All of the above, plus the gradual degradation of any opto isolators.