An express diagnostic method for ESD simulators and standardized ESD test stations

The management of ESD simulators and standardized ESD test stations to assure quality test results continues to be a major concern for test houses. Early detection of malfunctioning ESD equipment is possible if a day-to-day check is performed. The standard system for verification of ESD simulators is large, expensive and not practical for an everyday check. This paper describes the express diagnostic method aimed to locate the problems with either the ESD simulator or the test station. A 100MHz....500MHz bandwidth oscilloscope can be used to measure the quasi-electrostatic field of the horizontal coupling plane after the package of discharges has been applied. The malfunction of an ESD simulator and/or test station is discovered as a deviation from the baseline measurements, which are taken immediately after calibration. This method exposes any changes of the indicated discharge voltage or the horizontal coupling plane bleeder resistor impedance as well as changes in the discharge networks of ESD simulators. The oscillograms and the statistical analysis of data are presented in this paper, which support the claims that this method can assists in detection of potential problems of ESD equipment.