The Role and Selection of CBB Capacitors in Circuits

Main Functions

1. High-frequency filtering and decoupling
   In power supply circuits and high-frequency circuits, CBB capacitors are used to filter out high-frequency noise and interference, providing a stable voltage.
   Commonly used at the output of switching power supplies and inverters, they are employed in conjunction with electrolytic capacitors (electrolytic capacitors filter low frequencies, while CBB capacitors filter high frequencies).

2. Signal coupling and DC blocking
   In audio and signal transmission circuits, CBB capacitors block the DC component while transmitting AC signals to avoid mutual interference between the DC bias of the preceding and following circuits.
   Due to their low dielectric loss, they have minimal impact on signal distortion, making them suitable for high-fidelity audio circuits.

3. Resonance and oscillation circuits
   In combination with an inductor, CBB capacitors form an LC resonant circuit, used for frequency modulation, frequency selection, and oscillators (such as radios and wireless communication modules).
   They offer high capacitance stability, low temperature drift, and ensure the accuracy of the resonant frequency.

4. Pulse and energy storage
   CBB capacitors can withstand instantaneous high-current surges, commonly used in discharge circuits (such as camera flashes and lasers) and induction cooker resonant circuits.

5. Power factor compensation
   They are used for reactive power compensation in AC motors and lighting circuits to improve energy utilization efficiency.

Core Features (Advantages)

1. Low loss (low ESR)
   CBB capacitors have extremely low dielectric loss (tanδ), making them suitable for high-frequency and high-Q circuits.

2. High insulation resistance
   The leakage current is extremely low, which helps maintain charge and improve circuit stability.

3. Negative temperature coefficient
   The capacity decreases slightly with increasing temperature, but remains linearly stable and highly predictable.

4. Self-healing
   CBB capacitors can quickly restore insulation after partial breakdown, ensuring high reliability.

5. High pressure resistance
   CBB capacitors commonly have voltage ratings ranging from 63V to over 2000V, making them suitable for high-voltage applications.

Typical Application Scenarios

Consumer electronics: Audio crossovers, filtering circuits, power adapters.
Industrial control: Frequency converters, motor drives, power compensation cabinets.
New energy: Photovoltaic inverters and charging piles.
Specialized fields: High-frequency heating equipment, electric pulse equipment, and medical high-voltage instruments.

Selection Considerations

Voltage margin:

It is recommended that the working voltage be ≤ 50%~70% of the rated voltage (especially in high-frequency environments).

Frequency characteristics:

Capacity will decrease at high frequencies, so it is important to refer to the frequency-capacity curve in the datasheet.

Alternative solution:

For high-frequency applications, CBB capacitors can be compared to MLCC (multilayer ceramic capacitors), but CBBs have larger capacitance and higher voltage ratings.

For cost-sensitive applications, CL capacitors (polyester film capacitors) may be considered, but they have higher losses at high frequencies.

Comparison with Common Capacitors

Summary

CBB capacitors, with their low loss, high stability, and high voltage resistance, have become indispensable components in high-frequency, high-power, and high-precision circuits. When selecting a CBB capacitor, factors such as circuit frequency, voltage stress, cost, and space must be considered to achieve the balance between performance and reliability.