Is there a way to calculate overall PCB thermal resistance or thermal conductivity of a PCB based on the PCB stackup information? I would like to use this input in thermal analysis of the PCB. Thanks.

 

https://resources.altium.com/p/pcb-thermal-conductivity may help

 

https://resources.altium.com/p/pcb-thermal-conductivity may help

Thanks Jerry. However, it doesn't provide any equations or method to estimate the thermal resistance of a specific stackup with defined copper and substrate thickness.

 

Thanks Jerry. However, it doesn't provide any equations or method to estimate the thermal resistance of a specific stackup with defined copper and substrate thickness.

If you scroll down towards the botton, it recommends "Altium Designer" software. The thermal conductivity of PCB material is about two orders of magnitude greater than copper (except with ceramic substrates), although the copper layers are much thinner. Knowing the thicknesses of both, and the thermal conductivity of both you can probably do some rudimentary calculations and/or use a spreadsheet to work out how fast heat travels across the "wall" but I'll bet that good software will use a finite elements approach. In steady state the temperature gradient across the wall will be small.

Air flow is probably a more important consideration. Speed of travel through the PCB becomes fairly irrelevant when the whole stack is in steady state. Blown air would make all the difference but for natural convection the stack should be made with PCBs standing vertically.

Without professional software I'd simply recommend building a prototype and measuring temperatures near hot spots.