I am repairing battery charger. It has 6 STP180N55F3 mosfets, 3 are gone. Can I replace it with IRFB7440PBF? In datasheet they seem similar, except power discipation. STP180N55F3 says 300W, IRFB7440PBF says 208 but it has countinous dran current 208A while STP180N55F3 has 120A? I have some other options like IPP023N10N5AKSA1 but it is 5 times more expensive
The difference in nominal power is due to junction to case thermal resistance, it may matter if you are operating the transistor on huge heatsink with less than 2 K/W per transistor.
I would be more concerned about the lower Vdss of 40 versus 55 V. Are you sure there's sufficient voltage margin?
I didn't study the board layout so much, but as I saw theese mosfets are going directly to outputs (3 outputs for 3 different batterie banks). They dont have heatsinks, they are through hole mounted on the board. So my logic says that there cant be any voltage higher then 14.5 on source/drain of theese mosfets because charger is for 12V batte