Covaci Corina, Gontean Aurel
Applied Electronics Department, Politehnica University Timisoara, 300006 Timișoara, Romania.
Sensors (Basel). 2022 May 19;22(10):3869. doi: 10.3390/s22103869.
Multilayer Ceramic Capacitors (MLCC) have a major role in modern electronic devices due to their small price and size, large range of capacitance, small ESL and ESR, and good frequency response. Unfortunately, the main dielectric material used for MLCCs, Barium Titanate, makes the capacitors vibrate due to the piezoelectric and electrostrictive effects. This vibration is transferred to the PCB, making it resonate in the audible range of 20 Hz-20 kHz, and in this way the singing capacitors phenomenon occurs. This phenomenon is usually measured with a microphone, to measure the sound pressure level, or with a Laser Doppler Vibrometer (LDV), to measure the vibration. Besides this, other methods are mentioned in the literature, for example, the optical fiber and the active excitation method. There are several solutions to attenuate or even eliminate the acoustic noise caused by MLCC. Specially designed capacitors for low acoustic levels and different layout geometries are only two options found in the literature. To prevent the singing capacitor phenomenon, different simulations can be performed, the harmonic analysis being the most popular technique. This paper is an up-to-date review of the acoustic noise caused by MLCCs in electronic devices, containing measurements methodologies, solutions, and simulation methods.
多层陶瓷电容器（MLCC）因其价格低廉、尺寸小、电容量范围大、等效串联电感（ESL）和等效串联电阻（ESR）小以及频率响应良好，在现代电子设备中发挥着重要作用。不幸的是，用于MLCC的主要介电材料钛酸钡，会由于压电和电致伸缩效应使电容器振动。这种振动会传递到印刷电路板（PCB）上，使其在20赫兹至20千赫兹的可听范围内产生共振，从而出现电容器啸叫现象。这种现象通常用麦克风测量声压级，或用激光多普勒振动计（LDV）测量振动来检测。除此之外，文献中还提到了其他方法，例如光纤和有源激励法。有几种解决方案可以减弱甚至消除由MLCC引起的声学噪声。专门设计的低声学水平电容器和不同的布局几何结构只是文献中发现的两种选择。为了防止电容器啸叫现象，可以进行不同的模拟，谐波分析是最常用的技术。本文是对电子设备中MLCC引起的声学噪声的最新综述，内容包括测量方法、解决方案和模拟方法。
