Acoustic-noise reduction in printed circuit boards based on location and direction of multilayer ceramic capacitors

Multilayer ceramic capacitors (MLCCs) consist of multiple ceramic layers causing vibration owing to its piezoelectric characteristics. The vibrations are transmitted to the printed circuit board (PCB), causing acoustic noise. The mounting location and direction of the MLCC are crucial factors for reducing the acoustic noise. This paper presents a novel method for determining the optimal location and direction of MLCCs to reduce the acoustic noise. The excitation force of MLCC was simplified to calculate the vibroacoustic response of the PCB efficiently. Two design variables representing the MLCC location and direction were developed, and optimization problems were defined to minimize the acoustic noise. To validate the proposed method, the optimization problems were solved for an M.2 solid-state drive model under various scenarios. The results demonstrated that, on average, the overall sound power level was reduced by 4.59 dB for a single MLCC and 6.04 dB for multiple MLCCs.