The C2M0025120D datasheet, on page 3 (see attached picture) shows the characteristic curves of the drain-source on-state resistance Rds as a function of temperature T (on the right) and drain current Id (on the left).
I want to create a mathematical analytical loss model that specifies Rds as a function of T AND Id. For this reason, I want to use these two characteristic curves.
However, I noticed something that makes my approach impossible. Rds(T) (on the right) was measured at Id = 50 A. If we assume a gate-source voltage Vgs = 20 V, we can read the value: Rds(T = 150 °C) = 41.1 mOhm at Id = 50 A. I have assumed that this value matches Rds(Id) (on the left) at 150 °C, Id = 50 A and Vgs = 20 V. But if we take a closer look, we can see that at Id = 50 A and 150 °C a much higher resistance is reached: Rds(Id = 50 A) = 47.5 mOhm at 150 °C. So, the curves can't help me, because for some reason Rds(T = 150 °C) at 50 A is not equal to Rds(Id = 50 A) at 150 °C.
- Have I understood this fact of the characteristic curves correctly?
- Which characteristic curves could help me?
- What are sources that I can use, dealing with the modelling of Rds as a function of T AND I. I have read some papers that describe the modelling of Rds(T), but found none that deal with Rds(T,I) or at least Rds(I).