Study of turn-on characteristics of SCRs for ESD protection with TDR-O and TDR-S TLPs

There are few good evaluation methods to evaluate CDM ESD protection performance such as device turn-on speed, etc. A new current-waveform-based method to evaluate the turn-on speed of an ESD protection device is proposed. The method uses two Transmission-Line Pulse (TLP) Tester to investigate the turn-on characteristics of SCR and related devices. Both intrinsic and normalized turn-on conditions are defined for protection devices to study the different factors that affect the turn-on characteristic under various conditions. The turn-on of both forwardly and reversely working of devices is measured for the CDM model including positive and negative currents. From the experimental results, it is concluded that NMLSCR's performance is superior to PMLSCR in turn-on speed; MLSCR requires higher It1 to be turned on; and the turn-on speed of a PMLSCR decreases significantly with small increases in pulse amplitude under intrinsic working condition while NMLSCR and LSCR do not exhibit such property.