Systematic design technique for improvements of mobile phone's immunity to electrostatic discharge soft failures

A systematic design technique for the improvements of the mobile phone's immunity to the electrostatic discharge (ESD) soft failures is proposed. The design technique consists of two parallel processes; one is the ESD simulation and the other is the ESD characterization. The modeling methods of the mobile phone, the ESD gun and the ESD testing setup for the ESD simulations are also developed. The proposed technique is applied to design the countermeasures against the ESD soft failure of the slide-type mobile phone and the root causes of the ESD soft failure are analyzed based on the proposed technique. 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 failure. The improved mobile phone's ESD immunity is characterized again and no ESD soft failure is detected.