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Thermal analysis

Hi

I'm Jacob Johnson. I want to design a board in which MOSFETs are used as switching devices. In this design I want to calculate the PCB temperature while FETs are dissipating Pdis watts. So I need the thermal resistance of the FET case to ambient, but there is no simple equation for this value. Now I want to ask you a document or reference about this matter that explains how to calculate case to ambient thermal resistance.

Regards

Jacob

  • Hi Jacob,

    Thanks for your interest in TI MOSFETs. Please see the blog below for more information on thermal impedance. TI MOSFET datasheets include thermal impedance specifications: RthetaJA and RthetaJC. For most of our FET packages, junction-to-case is measured to the thermal pad on the bottom of the package. We typically do not specify junction-to-case to the top side of the plastic package. If there is a particular device/package that you are interested in using, we may have estimates for junction-to-case to the top side.