Impact of ESD strategy on EMC performances: Conducted emission and DPI immunity

In particular cases, system level stresses such as EMC stress (Direct Power Injection, Bulk Current Injection, and Radiated Field) and ESD gun stress are directly applied to the integrated circuits with no external protections [1]. Consequently, the integrated circuits have to be optimized to survive against severe external aggressions but also to ensure normal operations during the electromagnetic stress. The ESD strategy as well as the architecture of the ESD protections can significantly impact on the EMC performances. Unfortunately, the simulation of functional performances during EMC and ESD events remains very challenging for analogue products due the frequency domain and to the high injection mechanisms. This paper describes two case studies where the ESD protections significantly impact the conducted emission (CE 150ohm: first case study) and the conducted immunity (DPI: second case study) performances. Failure mechanisms will be explained and design optimizations fixing EMC issues will be presented. Benefits of the new design solutions will be quantified with EMC test measurements.