Whitepaper

Introduction to EMI: Standards, Causes and Mitigation Techniques

Published by Texas Instruments

This technical article from Texas Instruments provides a foundational overview of electromagnetic interference in modern electronic systems. As circuits become denser and more interconnected — exemplified by automotive camera modules packing imagers, serializers, and PMICs in close proximity — EMI becomes a critical design consideration. The article explains how EMI manifests through both conducted and radiated pathways, and outlines key standards such as CISPR 25 for automotive and CISPR 32 for multimedia equipment. Switch-mode power supplies are identified as a primary EMI source, with discontinuous input currents affecting frequencies below 30 MHz and fast switching edges impacting higher bands. Conventional mitigation approaches like LC filters and slew-rate reduction involve trade-offs in power density and efficiency. TI addresses this by integrating advanced techniques into its converters, including spread spectrum, active EMI filtering, cancellation windings, and package innovations tailored to specific frequency bands.