What does the internal temperature sensor measure?

[PCicc.1]

We are using an STMF4 and STMF3 in our product and are trying to see if we need to switch to the industrial variant for the extended temperature range.? Is the internal temperature sensor measuring the Die temperature, and if so is that essentially reading the junction temperature?

Thank you,

-Patrick

[S.Ma]

I would assume yes, unless there is a temperature gradient across the die's surface.

[TDK]

"Junction temperature, short for transistor junction temperature, is the highest operating temperature of the actual semiconductor in an electronic device."

So it's not exactly that. Unlikely that VSENSE is located exactly the highest temperature, but it's on the die and there's not a lot of temperature variation possible in such a small distance.

Note also the rated temperatures are typically ambient. Datasheet has better info.

I've taken many chips up to 85 C ambient and operated temp and never had issues.