"Joerg"
Phil Allison wrote:

Who said power mosfets don't suffer " punch- through" like BJTs do ?

Pics are of an Hitachi 2SK176

Nch lateral, 125 watt, 200 volt, 8amp.


Impressive! How'd you do that?


** Was like that when I found it - inside a 1000 watt per ch power amp.

Seems a DC arc started up from the drain pin to the nearest part of the
case, eventually self extinguishing when a large enough hole was burnt
through.

The somewhat overheated drain pin detached from the glass seal leaving the
small hole you see in one pic.

It's a rare event, but I have seen one other similar example and just one
involving a BJT.

The trigger event for the DC arc is the bonding wire from the drain or
emitter pin fusing.




...... Phil