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.