I'm curious about what the catch must be with some MOSFETs and their current ratings?? I mean an IRF3205 states 110A in a TO-220 case.... I would imagine the pins vaporizing before 110A made its way through?? Even a short pulse at this current - really??
Lee

 

Those are so called bollocks numbers. In the IR datasheet there is a note 5 attached to that figure, which states "Calculated continuous current based on maximum allowable junction temperature. Package limitation current is 75A."

So unless you are using the tab directly as one connection and the other pin is very very short and going into multiple huge thick pcb traces you will never get even close to those numbers.

 

Did you read the note?
Calculated continuous current based on maximum allowable
junction temperature. Package limitation current is 75A

Also if you have a time try read this
http://www.mcmanis.com/chuck/robotics/projects/esc2/FET-power.html