Can someone explain why using a ceramic capacitor with a high capacitance value (like 100µF) could potentially cause issues in circuits with sensitive analog signals or fast switching power supplies?
Using a ceramic capacitor with a high capacitance value (like 100µF) in circuits with sensitive analog signals or fast switching power supplies could potentially cause issues due to the following reasons:
- Piezoelectric Effect: Large ceramic capacitors, especially in the X7R or Y5V dielectric class, can exhibit piezoelectric properties. This means they can physically vibrate in response to electrical noise or fast switching signals, which may introduce unintended noise or distortion into sensitive analog circuits. This noise can interfere with the performance of sensitive analog signals or high-speed digital circuits.
- DC Bias Effect: In ceramic capacitors, especially high-capacitance ones, the actual capacitance decreases significantly under a high applied DC voltage (DC bias). This reduction in capacitance can affect the filtering or decoupling performance, which can be critical in power supply stability or analog signal integrity, leading to unpredictable behavior.
- High-Frequency Performance: While ceramic capacitors generally have good high-frequency characteristics, larger capacitance values tend to have higher (ESR) Equivalent Series Resistance and Equivalent Series Inductance (ESL), which can limit their effectiveness at filtering high-frequency noise. This could cause issues in fast switching power supplies, where maintaining low noise at high frequencies is essential for stability and efficiency.
- Capacitor Tolerance: High-capacitance ceramic capacitors, especially in non-C0G/NP0 classes, often have poor tolerance and stability over temperature and voltage variations. In circuits that require precise capacitance for analog filtering or timing, this variability could lead to performance degradation or unreliable behavior.
For these reasons, other types of capacitors, such as tantalum or electrolytic capacitors, may sometimes be more appropriate for higher capacitance values in circuits with sensitive analog signals or fast switching power supplies.
@gilshultz
Please tell us, in all your future posts, which part of your post is Ai generated. Seeing this Ai crap is getting annoying. Makes me think you don't know it yourself, and still want to say something.
Leo..
3 Likes
Probably all of it. Out of curiosity I put the question in Chatgpt and get the same and then some of the bladiblablabla.
Sigh.....
What rumors have you heard, and for what purpose do you want to use a ceramic capacitor of that size?
The proper word for why this can cause problems is that they are microphonic.
thanks
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