Hello, the temperature has little impact on the turn off time of the MOSFET itself, but it does effect the breakdown voltage of the MOSFET. A higher temperature will result in a higher breakdown voltage. This in turn means the inductor will discharge quicker and the time in avalanche will be shorter.
I'm going to try my luck here. If I have a IGBT that keeps having EOS failure near the aluminum wirebond, does it mean it could be UIS? If so, where would be the source? A hole is punched through the silicon, near the heel of the wirebond but not next or underneath it.
Well today's your lucky day then, @kevint1160. We passed your question to one of our IGBT engineers and received the following reply - What he described is most likely IGBT exceeded the RBSOA region, meaning overcurrent or over voltage. Does this answer your question? Please let us know if you need more information. Have a great day!
According to your description, it should not be the UIS, if it is UIS, normally the corner of the chip will be destroyed easily. It could be caused by exceed RBSOA, which may burn a black dot around the bonding wire. So, better to check your current or driver IC to see whether there is too big current flow through your IGBT during test.
@@Nexperia Thank you very much Sir for another response. It's funny because it hits 1 of the 3 IGBTs more specifically. Sometimes it burned at the passivation area of the emitter, far away from the wirebond. The real kicker is the fallout rate after removing and replacing just the damaged IGBT is about 15x less even though we did not replace any other component or IC. We are growing a bald spot from all the head scratching.
Hello, thanks for your question. If you did not want to avalanche the MOSFET, then it is perfectly acceptable to place a Zener diode parallel to the drain-source of the MOSFET. The Zener will need to have a lower breakdown voltage than the MOSFET over the intended current and temperature range. Alternatively, Zener clamps can be placed gate-to drain, holding the MOSFET in a highly resistive mode to dissipate the energy. However, this holds the MOSFET in linear mode, and generally speaking MOSFETs are more capable in avalanche than in linear mode.
