Thermal aware design methodology for small signal discrete products

A methodology for electro-thermal simulations of discrete semiconductor devices on PCB level is presented. By combining the finite element simulation tools FloTherm and Sentaurus the computation time can be reduced so that it is possible to include the surrounding ambient into the electrothermal model. This is achieved by extraction of thermal resistances using FloTherm which are inserted into Sentaurus as thermal boundary conditions. This approach has been verified with thermal measurements for a set of discrete devices in different packages and PCB layouts. The simulation results agree well with measurement.