Abstract: Characteristics of a power MOSFET gate charge test waveform are evaluated to yield a highly reliable and uniform testing methodology that replaces the inconsistent and inefficient dv/dt immunity testing currently performed. The invention utilizes the ratio of QGD over QGS1 to replace traditional dv/dt immunity testing in order to perform binning and sorting the devices. The ratio of QGD over QGS1 has proven to be a very reliable substitute for standard dv/dt immunity tests, and a very accurate predictor of a power MOSFET's suitability for a specified purpose. Because the gate charge parameters are relatively easily measured with high accuracy, and independent of test set-up or tester, reliability is far greater than previous methods and improved efficient results. Additional ratios of charge parameters enhance the performance of the testing methodology of the present invention.