This application note discusses the effects of electrical fast transients (EFT) on embedded controllers and recommends hardware and firmware techniques to mitigate them. This application note also explains a set of guidelines that a designer can use to build a system that is immune to such transients.International standards have been developed to describe the characteristics of transients. These standards also provide guidance to the product designer on the testing methodologies for compliance. The fast transient immunity requirements for electronic products are defined in IEC 61000-4-4 (for EFT) by International Electrotechnical Commission (IEC).