Here's another one.
I have sourced what I think is an appropriate low Rds(on) Logic Level N channel MOSFET, to switch a TEC module using Arduino PWM (Tellurex FAQ, point 41).
771-PSMN1R6-30PL,127 NXP (Phillips) MOSFET
Basic specs are - 30v, 306w, 100A - Qds (Vgs 4.5v dynamic, 25A) - Rds(on) 1.7 mOhms (Vgs 10v, 25A, static).
First question - is this the correct rating for the type of application? not sure about the Rds(on) 1.7mOhms Vgs 10v static spec. Should that be ~4.5v, and is the Rds(on) sufficiently low?
Second question - Will several FET's in parallel solve overheating of the FET due to lower drain source resistance.
Third question - If I run these in parallel to lower the Rds(on) how many is practical?
I have managed to burn out one or two. They get incredibly hot without resistance on the TEC -ve to FET Drain. In-fact I can only run the FET without a heat sink at about 2 - 3v, with very hot resistors, and this translates to ~10C cooling. The system at full blast is capable of ~34C differential.
TEC specs - 12V, 8A.