Which type of capacitor has lower 1/f noise: MLCC or film?

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In summary: The white noise spectrum of a resistor will always be low-passed by the capacitors in the circuit, so you would never be able to measure the input referred noise in this way.In summary, piezo effects, buzz, and capacitance all play a role in the inherent noise of a capacitor.
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I am working on a low noise capacitive feedback TIA where I need to achieve a pretty low voltage/current input referred noise and so I started researching components. For the resistors and transistor I know about 1/f noise, etc. and I'm confident in my choice but it dawned on me, what about the capacitor?

I've read about piezo effects in ceramics, buzz in film, and all the various ways capacitance can change on you but I haven't seen much on how dielectric choice effects inherent noise.

Basically I am trying to pick between a 47pF 0603 film or a NP0 MLCC. It seems like antidotally, in the acoustic band anyway, they both have pros/cons. Input referred noise at the level I'm working at is a pretty labor intensive measurement to take so I'm really hoping to pass on the first try. :)
 
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TIA = transimpedance amplifier

Capacitors do not generate 1/f noise in the same way a resistor does.

MLCC = MultiLayer Ceramic Capacitor = skycap; are designed for use on power supplies, when they leak they will self-heal if across a low impedance supply, but they remain leaky if used for low-power signals. While they are leaky they will make noise.

Use silver-mica, or film, not MLCC for signals.
 
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Baluncore said:
Capacitors do not generate 1/f noise in the same way a resistor does.

On second thought that must be true. If it wasn't we couldn't low pass the white noise spectrum of the resistor, and clearly noise shaping is a thing.

Somehow I am just really surprised by that. I am probably overthinking it. :)
 
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It certainly isn't the case that there is NO 1/f noise in capacitors, pretty much everything exhibits 1/f noise at some level, but the 1/f noise should under most circumstances be lower than in a resistor.

Specifically, the dielectrics are intrinsically noisy at some level (even really pure silicone exhibits some dielectric noise) and in some applications this can be problematic, especially for RF/MW applications.

That said, I very much doubt this is something you could need to worry about in this application.
 
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1. What is 1/f noise in capacitors?

1/f noise, also known as flicker noise, is a type of electrical noise that occurs in electronic components, including capacitors. It is characterized by fluctuations in the electrical current or voltage that follow a 1/f frequency dependence, where f is the frequency. This type of noise is often undesirable as it can interfere with the performance of electronic devices.

2. What is an MLCC capacitor?

MLCC stands for Multilayer Ceramic Capacitor. It is a type of capacitor that is made up of multiple layers of ceramic material and metal electrodes. MLCC capacitors are commonly used in electronic circuits due to their small size, high capacitance, and low cost.

3. What is a film capacitor?

A film capacitor is a type of capacitor that is made up of a thin plastic film as the dielectric material. The film is coated with a metal electrode and then wound into a cylindrical shape. Film capacitors are known for their high precision, stability, and low losses, making them suitable for use in a wide range of electronic applications.

4. Which type of capacitor has lower 1/f noise: MLCC or film?

Generally, film capacitors have lower 1/f noise compared to MLCC capacitors. This is because the ceramic material used in MLCC capacitors can exhibit piezoelectric effects, which can contribute to 1/f noise. On the other hand, the plastic film used in film capacitors does not exhibit this effect, resulting in lower noise levels.

5. Are there any other factors that can affect 1/f noise in capacitors?

Yes, there are other factors that can affect 1/f noise in capacitors, including temperature, voltage, and frequency. Higher temperatures can increase 1/f noise, while higher voltages and frequencies can decrease it. Additionally, the quality and construction of the capacitor can also play a role in the level of 1/f noise. It is important to consider all of these factors when selecting a capacitor for a specific application.

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