Leadless devices for EMI suppression

Abstract

Electromagnetic interference by unwanted signals/noise and electrostatic discharge, electromagnetic induction, thunder/lightening etc. has come in to focus due to the malfunctioning of sophisticated control, test, measurement and a host of other systems resulting in serious consequences. The drive towards miniaturization and lower power consumption in portable electronic equipment is driving towards lower driving voltages. Interference from the aforementioned sources such as static electricity discharge from the human body and other sources has become a serious problem for modern equipment. Electronic equipment is therefore enclosed in specially conducting enclosures. Special components are used to protect the equipment from unwanted EM noise etc. Traditionally these surge and EMI suppression components were leaded type as they were easily accommodated in large size equipment. Currently leadless EMI and surge suppression components are essential to the miniaturization of modern portable electronic equipment and for ensuring their reliability and efficient working in hostile EM environments. The present paper gives a very brief discussion of the essential devices, which have been developed in the leadless format suitable for incorporation in portable electronic products. The components include surge suppression devices (gas discharge tubes, metal oxide varistor, zener), and noise suppressing/filtering components based on soft ferrite, capacitors (plastic film, multi-layer ceramic and tantalum electrolytic) and other composite devices. A very brief of the miniaturization technologies other then EMI/EMC components is also described.