There is a growing need for commercial and military power electronics to operate above 175 °C. Changes in operating parameters at 200 °C have been measured for three devices, an NPN bipolar junction transistor (BJT), an N‐channel insulated gate bipolar transistor (IGBT), and a N‐channel metal‐oxide‐semiconductor field effect transistor (MOSFET). Using the results of these changes, a power supply for 200 °C operation has been built for lifetime tresting of the IGBT and N‐MOSFET.