Ceramic Capacitors: Advantages and Disadvantages

This page explores the advantages and disadvantages of ceramic capacitors, along with a basic introduction to what they are.

What is a Ceramic Capacitor?

Introduction: A ceramic capacitor is a capacitor that uses a ceramic material as its dielectric.

There are two main types of ceramic capacitors, based on their construction:

• Multi-Layer Ceramic Capacitor (MLCC)
• Ceramic Disc Capacitors

They are typically available with small values, ranging from 1 nF to 1 µF. However, ceramic capacitors with values up to 100 µF are also possible to design.

They come in small sizes and with low maximum rated voltage. Importantly, ceramic capacitors are non-polarized, meaning they can be connected to an AC supply. They also offer good frequency response due to their low parasitic effects. These capacitors are often used for bypass and decoupling applications.

As shown in the figure above, a disc-type ceramic capacitor has two conductive discs on either side of a ceramic insulator. Leads are attached to both of these plates, which are coated with a waterproof ceramic composition. This type of ceramic capacitor is available up to a value of 0.01 µF and can withstand DC voltages up to 750 V and AC voltages up to 350 V.

MLCC-type ceramic capacitors consist of multiple layers of ceramic material (such as barium titanate) separated by metal electrodes. This construction effectively forms many capacitors in parallel. An MLCC can be composed of hundreds of ceramic layers, each functioning as a single ceramic capacitor. In fact, MLCCs can consist of 500 layers or more.

MLCCs are available with values less than 1 µF, and also in the 10 to 100 pF range. They typically withstand voltage ratings of 50 Volts or less. MLCC-type ceramic capacitors are often used for high-frequency filters.

The table above shows tolerance values for disc ceramic capacitors. For example, the code “104K” represents a value of 10 x 10⁴ pF, which equals 100 nF with a tolerance of +/-10%, as indicated by the code “K”.

Ceramic capacitors are categorized into Class-1 and Class-2 based on their intended applications. Class-1 capacitors are used for applications requiring higher stability and low losses. Class-2 capacitors are used where high capacitance per volume is needed.

Advantages of Ceramic Capacitors

Here are some of the benefits of using ceramic capacitors:

• Reliable: They offer good frequency response characteristics, even at higher operating frequencies.
• High Voltage Withstand: They can withstand voltages up to 100 V.
• Lightweight: They are relatively light.
• Inexpensive: They are generally inexpensive.
• Versatile: They are available in various shapes and sizes.
• Low ESR and ESL: They offer low Equivalent Series Resistance (ESR) and low Equivalent Series Inductance (ESL).

Disadvantages of Ceramic Capacitors

Here are some of the drawbacks of using ceramic capacitors:

• Limited High Capacitance Values: It is difficult to achieve high capacitance values with their construction. Capacitance values are typically limited to about 150 µF.
• Voltage Limitations: Higher voltage ceramic capacitors with the standard construction are not readily available. Power ceramic capacitors are designed with larger physical shapes and sizes to withstand higher voltages, ranging from 2 KV to 100 KV.
• Temperature Sensitivity: They have a relatively large temperature coefficient.
• Higher Tolerance Values: Ceramic capacitors tend to have higher tolerance values.
• Stability Issues: Some power supply circuits may not be stable when using ceramic capacitors as output capacitors.
• Cracking Concerns: Larger size capacitors are prone to cracks when the PCB flexes. Therefore, several smaller units are often used in parallel instead.