Accurate SPICE Model Development for 650V GaN Transistor Using 2-Port S-Parameter Measurements

Paper in proceeding, 2025

Accurately modeling GaN transistors is crucial for predicting their high-speed switching behavior in power converter circuits. GaN transistors are characterized for their low on-resistance and rapid switching, but parasitic effects and nonlinear capacitance must be carefully accounted for to ensure reliable simulations and proper operations during the high-speed switching process. This work presents a characterization technique based on 2-port S-parameter measurements to directly extract parasitic inductances, resistances, and intrinsic capacitances of a commercial 650 V GaN transistor. The extracted parameters are used in a physics-based model that describes both static and dynamic device behaviors. The resulting SPICE-compatible model is benchmarked against the supplier's model and double-pulse test (DPT) results in a half-bridge configuration. The proposed model closely matches the resulting switching waveforms and successfully reproduces high-frequency ringing effects due to the parasitic components. This demonstrates the model's predictive fidelity and underscores its practical relevance for GaN-based power converters, particularly in accurately representing converter circuit behavior under oscillatory conditions. The key contribution of this work is a practical and SPICE-compatible GaN transistor modeling methodology that covers a broad-range characterization (up to 200 MHz and 500 V) with minimal reliance on specialized tools or proprietary data.