In this paper, the influence of the parasitic capacitance of a magnetic component (inductor or transformer) on the switching of 600V cascode GaN HEMT devices is investigated. An analytical switching model is used to analyse the influence and the results are verified by means of an experimental double pulse tester setup. Furthermore, the influence of replacing the diode of the switching cell with an active GaN HEMT switch is analysed in combination with the parasitic capacitance of the magnetic component.