Today's RF Power Applications Require Understanding Equivalent Series Resistance And Q Factor

By Steve Hopwood

As a fundamental component of circuit design, equivalent series resistance (ESR) is the measurement of all the non-ideal electrical resistances in series with a capacitor. When current flows through a multilayer ceramic capacitor (MLCC) due to application of alternating voltage, heat is generated in the MLCC due to the losses, specifically ESR. As a result, this self-heating can cause various performance and reliability issues in the circuits of today’s more complex and smaller electronic systems. Related to ESR, quality factor (Q factor) is also an important figure of merit used to compare MLCC’s.