The high edge rates of wide bandgap semiconductors can produce common-mode currents that flow through the baseplates of power modules. The module baseplate capacitances are a significant contributor to the high-frequency emissions of wide bandgap applications. Unfortunately, the measurement techniques currently available to characterize parasitic baseplate capacitances are either challenging to perform or require module deconstruction. This paper proposes a simple and non-destructive measurement technique to characterize the baseplate capacitances of multi-chip power modules on a per-terminal basis. The technique can be performed with an impedance analyzer and does not require any special fixturing or alterations to the module.
