Interconnects for device ESD protection

A conductive spring loaded shorting bar on the leads of a TO-220 MOSFET was found to protect it from ESD failures. The MOSFET is used in an implantable cardioverter defibrillator device where quality and reliability is essential. Pre-production samples revealed significant ESD failures, thought to be associated with a mechanical shearing operation. Analysis suggests CDM failures, since testing revealed a low CDM threshold. A custom designed removable shorting interconnect raised all ESD thresholds by at least an order of magnitude.