I am doing power dissipation of a power mosfet. My design requirements are :-
- 20A @ 12-20V (Ambient temp will be around 50 deg Celsius)
The mosfet I am using is :-
My doubts are :-
In the datasheet , they have given 2 types of power dissipation as below :-
I understand that they are at different case & ambient temperature but what do they actually mean & how to use this data?
In one more table they have given :-
Rja is given & Rjc is given. Rja = Rjc + Rca. Rca is not mentioned anywhere because that might depend on the PCB layout but still, how do I calculate Rca to do my thermal analysis.
In general, what do I actually use for thermal analysis. If @ an assumed junction temp of 70 deg c, my Rdson is 20 mE & my current is 20A. calculating :-
P= (I2)Rdson = 400*.02 = 8W.
Is 8W okay through this mosfet? If not, how to prove that?If yes, how to validate?