I am using standart N-channel MOSFET (Fairchild FDS6676) switch like in this picture:
Load is actually 10A resistive and 27V power source is fused with 15A non-recovery fuse. I am driving it directly from 3,3V logic - ARM MCU.
I know that MOSFET will be quite stressed because it is designed for 14,5A continuous current and 10A will be drained for sure. There might me some peaks to 12-13A for few miliseconds. As I calculated, there will be about 3-4W of power loss on this MOSFET.
I have heatsink mounted, but still concerned about reliability (always with thermally stressed parts). In case of MOSFET break/malfunction (overcurrent peak above 14,5A or over-temperature failure), MOSFETS often shorts all terminals, so I could get 27V to gate and directly to MCU port. In case that S-D burned together will blow my fuse, but in case only S-G not...
My question is - is TVS protection diode fast enought to protect MCU in such scenario? Or is there any better approach? I am considering Littelfuse AQ4020-01FTG-C.