Method of measuring characteristic impedance of electrostatic discharge protecting circuit and apparatus for realizing the same

摘要

A method of quickly measuring a characteristic impedance of an ESD protecting circuit by applying a discharge voltage to the ESD protecting circuit, includes the steps of measuring a variation in discharge voltage applied to and a variation in discharge current caused to flow through the ESD protecting circuit with time; simultaneously detecting a state when both the discharge voltage and discharge current corresponding to each other are attenuated, after both the discharge voltage and discharge current sequentially rise to arrive individually to respective peak values based on an input to or an output from a computer; and taking a ratio of the variation of discharge voltage to the variation of discharge current during the attenuation as an impedance value when the ratio is nearly constant as well as an apparatus for realizing the same.