Common mode inductor material selection

As government agencies continue to tighten the requirements for electromagnetic compatibility, design engineers are forced to pay closer attention to the emissions created by their products. This is particularly true for DC-DC converters. Their high switching frequencies and steep pulse slopes are an excellent breeding ground for EMI. One important component in the suppression of electromagnetic interference (EMI), is the common mode inductor. It offers a very high impedance over a wide frequency range and is an integral part of most EMI filters. This report explains the methods used in selecting materials for common mode inductors