Optimizing MOSFET Selection for EMC-Critical Automotive Applications

This paper investigates the effect of the Active Area and integrated Snubber Area of low-voltage silicon superjunction MOSFETs in a half-bridge configuration on the exhibited switching losses, ringing, and EMC performance. The damping factor is employed as a benchmark to quantify the oscillations in the drain current waveform. EMC sweeps were conducted to correlate the damping factor with electromagnetic interference levels, providing a quantitative link between oscillation behavior and EMC performance. Experimental characterization is performed on a range of devices to demonstrate the impact of the die parameters on the performance, which is then replicated through simulated testing. This research aims to identify the design choices used to select the optimal device layout for different automotive applications, including DC-DC converters, motor drives and isolation switches, based on their varying performance requirements. Alterations made to the Active Area were found to influence the parasitic capacitances of the device, resulting in a direct effect on the oscillatory behavior and associated losses. Devices featuring larger Snubber Areas demonstrated advantages in applications that necessitate strict automotive EMC standards.