Convert Watts to Temp 'C' 1

T = Ta + Rt * P ; where T = resulting temp; Ta= ambient T;
Rt = thermal resistance in C/Watt and P = power dissipated.


<nbucska@pcperipherals.com>

THANKS!!

Finding "Rt" is the hard part. Rt is not just the conductive resistance inside the heat source (theta j-c for chip packages), it's the resistance from the heat source to the ambient air (theta j-a).

Theta j-a includes conduction, convection, and radiation and can vary dramatically depending on nearby components, airflow, surface area, PCB copper, finish, etc, etc.

JEDEC has a standardized test that defines these variables -- very useful for comparing chip packages, but useless for predicting results in your system.

ko (