An RC snubber design method to achieve optimized switching noise-loss trade-off of cascode GaN HEMTs

The cascode gallium nitride high electron mobility transistors (GaN HEMTs) are very vulnerable to self-sustained turn-off oscillation due to their cascode configuration. This paper presents a design approach for the RC snubber of cascode GaN HEMTs to achieve the optimized noise-loss trade-off. At first, an analytical model is proposed to describe the instability of cascode GaN HEMTs-based test circuits utilizing RC snubber. Based on the model, an analytical approach is proposed to achieve two optimum RC snubber designs S1 and S2. The design S1 can satisfactorily dampen the oscillation with minimum switching losses. The design S2 achieves maximum effective damping on the oscillation at a minimized cost of additional power losses. In the end, the accuracy of the proposed model is validated by the double-pulse test and good agreement is obtained.