CSD25402Q3A: Junction To Board (Top) Theta Value

Hello Ray,

Thanks for the inquiry. I just answered this question from a customer - assuming this is the same. Here is a link -

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1111828/csd25402q3a-thermal-reistance

Here is my earlier response:

The junction-to-case thermal resistance, Rθjc (2.3°C/W max) is specified on page 3 of the datasheet. This is measured from the junction to the thermal pad (source) on the bottom of the package. Please visit the link below for more information on how TI tests and specs thermal impedance in our FET datasheets.

https://e2e.ti.com/blogs_/b/powerhouse/archive/2016/06/10/understanding-mosfet-data-sheets-part-6-thermal-impedance

Best Regards,

John Wallace

TI FET Applications

Hi Ray,

That's an interesting question. I do not believe there will be a significant thermal resistance contribution from the solder interface between the thermal pad on the package and the PCB since the solder is a very good thermal conductor. I did notice that your post had junction to board (top) in the subject line. TI does not provide the junction to case (top) thermal resistance because the primary path to remove heat from the package is thru the thermal pad and into the PCB. It is much higher than junction to case (bottom).

Thanks,

John

Hi Ray,

We only specify RθJC (bottom or board) and RθJA in our MOSFET datasheets. This can be found in the table on page 3.

Best Regards,

John