CSD16403Q5A: Power Dissipation when Tc = 25.

Hi Louis,

Thanks for your interest in TI FETs. I've included links below on MOSFET continuous current (and power) ratings and power dissipation capability of various power MOSFET packages. The power dissipation specified in the datasheet is a simple calculation: PD = (Tj - Ta) / RthetaJA, where Tj = maximum allowable junction temperature, Ta = ambient and RthetaJA = junction-to-ambient thermal impedance. To calculate the maximum power dissipation at Tc (case temperature) = 25degC, you can simply substitute Tc for Ta and RthetaJC for RthetaJA as follows: PD = (Tj - Tc)/RthetaJC = (150 - 25) / 1.8degC/W = 69.4W. This is a very large number and it usually not possible to dissipate this much power in this package unless you have an "infinite" heatsink capable of keeping the case temperature at 25degC. In practical terms, this package is capable of about 3W maximum dissipation with a good PCB design.