4.5 GHz time domain measurement of voltage transition duration due to micro gap discharge as low voltage ESD

Very fast transitions duration due to starting of gap discharge were investigated in the time domain. Voltage rising time in positive polarity and falling time in negative polarity were observed with a very wide-band transient digitizer. The gap space was set very small for voltages below 1500 V as a simulation of the CDM ESD and the gap discharge of switch devices. The measurement system consists of a distributed constant line system with a tapered coaxial electrode, which has a matched impedance for the characteristic impedance of the distributed constant line system. The insertion loss of the tapered coaxial electrode was within -3 dB in the frequency range below 4.5 GHz. The atmosphere around the electrode is ordinary air. This experimental system enables to measure the high speed transients of about 100 ps due to gap discharge in time domain. As a consequence of the experiment, the relationship between the discharge voltage and the transition duration were confirmed.