SEED Modeling of an ESD Gun Discharge to a USB Cable Surrogate

An IC protected by a transient voltage suppression (TVS) diode may fail if the TVS device does not turn on or does not turn on quickly enough, causing the IC to take the full brunt of the ESD event. System Efficient ESD Design (SEED) simulation can help predict when the TVS will turn on and the level of ESD stress seen by the IC. In the following paper, models are developed to predict the voltage and current through a TVS and on-chip protection diodes connected to a USB cable when an ESD gun discharges to a pin at the end of the cable. A hybrid simulation methodology is proposed, which uses a full-wave model of the ESD gun, cable, and enclosure combined with the ESD protection devices and test board's circuit-level models. The response of the ESD protection is studied in simulation and measurement for a variety of cable configurations. Simulations of the voltage and current waveforms match measurements 24-35%. The total charge delivered to the on-chip diode as a function of ESD gun voltage was predicted within 21%.