Multilayer ceramic capacitor sound quality

Why are multilayer ceramic capacitors so popular?

Multilayer ceramic capacitors (MLCCs) are immensely popular in many applications because of their volumetric eficiency and relatively low price. The advantage of this capacitor technology lies primarily in its use of special dielectric materials. To understand why, recall that the capacitance of a simple parallel-plate capacitor follows Equation 1.

Why do multilayer ceramic capacitors cause acoustic noise?

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.

Are ceramic capacitors a good choice for acoustic noise?

Capacitor manufactures have already developed ceramic capacitors with low distortion dielectric material, which exhibit lower ferroelectric properties and smaller deformation in regards to a voltage change. And there is a series manufactured by Murata that the capacitor is on interposer substrate to reduce the acoustic noise (Figure 2).

Can multiple ceramic capacitors be used in a DC-DC converter?

When multiple ceramic capacitors are used in a battery line (primary side of a DC-DC converter), the sound pressure level can be further reduced by implementing anti-noise measures for all of the capacitors in the same battery line instead of just some of them.

Why are multiple ceramic capacitors equipped on the same line?

Multiple ceramic capacitors with the characteristics described above are equipped on the same line. Voltage fluctuations easily occur in order to provide power to the CPU, camera, RF modules, and other circuits. With large component sizes/capacitance, the dielectric expansion/contraction due to the voltage application increases.

Are MLCC capacitors bad for audio?

MLCC capacitors are very popular, but they can significantly degrade the performance of an audio signal chain. It is possible to minimize the distortion from MLCC capacitors by using larger-value capacitors and increasing the load impedance that the capacitor sees.