Multilayer Ceramic Capacitor Vibration Source Model Library Development

When a multilayer ceramic capacitor (MLCC) is soldered on a printed circuit board (PCB), the capacitor deformation generates a force on the PCB, which serves as a source to excite PCB vibration and generate unwanted acoustic noise. A MLCC can be used under any loading conditions as long as the power supply voltage remains below its rated voltage; thus, the MLCC source mode can be extremely complicated because of different combinations including direct current voltage levels, alternating current noise amplitudes, and related frequencies. When the power rail is under different loading conditions, the PCB vibration amplitude can differ; however, the MLCC vibration source model should remain the same under a given condition. In this article, the MLCC equivalent source models are developed with a simplified method, and a source model library for the six MLCCs is constructed. A method for simplifying the MLCC equivalent source model is addressed from three aspects: frequency, power supply dc voltage, and ac noise amplitude. The developed source model library is validated by comparing the simulated and measured system vibration velocity. The proposed simplification method can significantly reduce model development efforts and enable the creation of a comprehensive source model library for MLCCs.