Question about juction temperature

chocolet3018

hello, i have a question about junction temperature.

I thermal simulation the chip (CPM2-1700-0045B) in LTspice.

However, I don't understand because it is very different from the chip (C3M0045065D) result.

The result of the chip (C3M0045065D) is that the heat gradually increases and then enters a steady-state.

but, in the case of chip (CPM2-1700-0045B) heat is generated only when switching is on/off, and heat disappears again in conduction state.

In my opinion, it is correct to gradually increase and then enter a steady-state like the result of chip (C3M0045065D).

Finally, I have two questions.

First, the chip (CPM2-1700-0045B) result come out properly? if yes, what is the junction temperature of chip?

Second, if the result of chip (CPM2-1700-0045B) is not correct, where should fix it?

Please let me know...😔