FiXtress compares the results of circuit simulations with the performance limits for the secure operation of components and identifies weak points in overloaded components. Overload of components may occur due to excessive power dissipation, junction -temperature overruns and current/voltage overruns. The overruns lead to problems with the MTBF, design performance, housing and cooling requirements. FiXtress enables a simulation based on the design data with simple and realistic electrical stress models easy to be obtained. Thus, problems can be detected at an early stage in the design process and reliable results can be developed.