Distortion of ESD Generator Pulse Due to Limited Bandwidth of Verification Path

The paper deals with analysis of how limited bandwidth of a setup for verification of electrostatic discharge (ESD) generators affects reliability of testing. It is investigated how suppression of a high-frequency part of an ESD pulse spectrum distorts the pulse waveform and affects its standardized time domain metrics: the rise time and the peak value. Restriction of a pulse spectrum is achieved by low-pass filtering with a defined passband. The filtering models high-frequency attenuation of a measurement path, in particular that of an oscilloscope. The analysis is conducted for theoretical ESD pulses, specified by the IEC Standard, as well as for series of real noisy pulses recorded on setups with wideband 6 and 12 GHz oscilloscopes. Discrepancies of rise times and peak currents of filtered pulses with respect to an original input pulse are calculated as measures of distortion due to constraint of a pulse spectrum. It is shown that above 3 GHz, the setup circuit noise is the main factor contributing to measurement uncertainty of the metrics.