Highly Integrated Multilayer Varistors for ESD/EMI Filtering Applications

摘要

The scope of this paper is to describe the filtering properties of highly integrated ESD/EMI filters based on state of the art multilayer varistor technology. Recently developed multichannel low pass filters with high attenuation between 800 MHz and 6 GHz will be presented and discussed.rnThe filter arrays have two main functions. They cancel out noise from the signal lines caused by electromagnetic interference (EMI) and provide a reliable protection of the circuit from the impact of electrostatic discharge (ESD).rnUsing a novel inner electrode design the functionality of up to 10 discrete components have been integrated into a single array in package size 0405 (1.0 x 1.4 mm). Up to 20 discrete components have been integrated into package size 0508 (1.25 x 2.0 mm).rnTwo types of filter designs have been developed. Firstly the feed through type filters provide extremely low insertion loss due to a very low integrated resistance (0.3Ω) beneficial in applications such as audio lines filtering. Secondly the RC-type low pass filters have a low line-capacitance and provide reliable EMI filtering of RF noise in LCD modules (LCM). The high cut-off frequency exhibits extremely low signal distortion in different kinds of high clock speed applications.rnAll new filter designs provide ESD protection that exceeds the requirements of IEC 61000-4-2 level IV, offering a highly stable filtering performance.