The device-set consists of an ultra fast CoolMOS (TM) and an ultra fast high voltage ThinQ!(TM) SiC-Schottky diode nearly reaches the performance (losses, frequency, ruggedness) of pure SiC technology. So, new fields of application can be opened with future converter generations in high frequency power electronics. To optimize the circuits, the influence of parasitic parameters of the power semiconductor devices and circuit topologies on the switching behavior has to be analyzed exactly. Therefore, a suitable simulation tool was developed and verified by measurements in a typical application circuit. Results of simulations and measurement are presented in this paper.