according to this page:
I have been looking for some high powered MOSFETs (>100A, preferably >200A) but so far, all I know is that a safe bet is to go with a ISOTOP package, but I don't even know the true amp capacity of that package either. Is there a document that lists the amp capacity of FET packages, so I can weed out the b.s. amp ratings of different MOSFETs? I can't seem to find such document anywhere....the TO-220AB package the FETs were installed in had a lower current limit than the FETs! Discussions with the International Rectifier FE and later with a rep from Motorola confirmed that the limits on the TO-220AB were approximately 75 amps. This limit was due to the heating of the lead frame to the point where the legs would melt. Not something you want to have happen on your board. So even though a FET like the IR1405 has a current spec of 169 amps, the package it is in will melt before it reaches that point. But more importantly, that 169 amp number was crap too, at least it wasn't usable.