Measurement Investigation on Acoustic Noise Caused by "Singing" Capacitors on Mobile Devices
Acoustic noise from mobile devices can be annoying for customers. Multilayer ceramic capacitors (MLCCs) soldered on printed circuit board (PCB) are known to be a main source of acoustic noise. The PCB in these devices feature hundreds of MLCCs. In this paper, a measurement methodology to identify the major vibrating MLCCs on board is presented. Laser Doppler vibrometer scanning result is used to find the dominant MLCC source. The correlation between board vibration and acoustic noise is confirmed with microphone probe. As a result of the piezoelectric properties of MLCCs, the root cause of the vibration is analyzed from an electric point of view. The problematic MLCCs are find to share the same power line which renders the same noise peaks as in the vibration and sound pressure measurements. After replacing the vibrating MLCCs with low acoustic noise MLCCs, the board clearly shows decreased level of vibration.
Y. Sun et al., "Measurement Investigation on Acoustic Noise Caused by "Singing" Capacitors on Mobile Devices," Proceedings of the 2019 IEEE International Symposium on Electromagnetic Compatibility, Signal and Power Integrity (2019, New Orleans, LA), pp. 505-510, Institute of Electrical and Electronics Engineers (IEEE), Jul 2019.
The definitive version is available at https://doi.org/10.1109/ISEMC.2019.8825220
2019 IEEE International Symposium on Electromagnetic Compatibility, Signal and Power Integrity, EMC+SIPI 2019 (2019: Jul. 22-26, New Orleans, LA)
Electrical and Computer Engineering
Electromagnetic Compatibility (EMC) Laboratory
Keywords and Phrases
Acoustic Noise; Color Map; Laser Doppler Vibrometer; Microphone; Multi-Layer Ceramic Capacitor; Vibration
International Standard Book Number (ISBN)
Article - Conference proceedings
© 2019 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.
01 Jul 2019