Electronics Forum / CAD / February 2008

I have a very small board that I would like to model for thermal
analysis.  I am pretty confident that I can get by with a first order
analysis since I only want to know if I have a prayer of a chance of
dissipating the heat from this board, rather than a detailed analysis
of the range of temperatures across the board.  I was thinking about
drawing a simple spice circuit with current to represent heat,
resistors to represent thermal resistance and voltage to represent
temperature.

Sounds pretty simple, right?  But even after doing some web searching,
I have no idea where to find details on the thermal conductivity of
PCB material and the values to use for transmitting heat from the
board to the air.  I am surprised that this is not commonly used, but
it appears that most IC data just *assumes* that your board is large
enough that it is a good heatsink.  I did not find a single reference
with info on the PCB.

Am I not looking hard enough?  Can anyone point me to the raw data on
PCB thermal characteristics I need for this analysis?