free on line calculator > temperature of package
That’s where this calculator comes in. With this tool, you can now estimate the temperature at the bottom of your package based upon the construction of the PCB. You set the package type, the power dissipated inside your package, the PCB board material, the via construction, and the base plate temperature (typically 85 ºC). The calculator then determines the temperature rise through the PCB to the bottom of the package, under the following assumptions: the PCB is plated with 1 oz. copper (1.4 mils thick), the package is attached to the PCB with solder (2 mils thick), and the base plate is an ideal heat sink.
However, we cannot state this enough: This tool is best used to get a ball-park estimate of the temperature rise from the base of the PCB to the bottom of your package. There are quite a number of variables to play with here so take your time. Again, if you find that the temperature at the bottom of your package is too high, we encourage you to verify the results with a finite element thermal analysis program such as ANSYS. If you need help with such analysis, please do not hesitate to contact us. Let us use our expertise to understand and solve your thermal problems. Cooler heads will prevail!