Systematic Analysis Methodology for Mobile Phone's Electrostatic Discharge Soft Failures

A systematic analysis methodology for mobile phone´s electrostatic discharge (ESD) soft failures is proposed. The proposed analysis methodology consists of two parallel processes: one is the ESD simulation and the other is the ESD characterization of the mobile phone. The ESD simulation models that consist of the ESD generator, the ESD testing setup, and a mobile phone are also developed and their accuracy is experimentally verified. The proposed methodology is applied to design the countermeasures against the ESD soft failure of the slide-type mobile phones and the root causes of the ESD soft failures are analyzed. The RC low-pass filters are designed to improve the ESD immunity of the mobile phone and the ESD simulation results of the improved mobile phone show more than 82% voltage-level reductions of the signals, which cause the ESD soft failures. In order to verify that the reduced voltage levels, actually, solve the problem of ESD soft failures, the improved mobile phone´s ESD immunity is characterized again, and no ESD soft failure is detected.