Semiconductor and Electronics

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What is a Multi-Layer Ceramic Capacitor and Why is it Used?

Author : Aparna | May 14, 2024

In the world of electronics, there is a common challenge that engineers and designers face: the need for compact and reliable components that can handle high capacitance values. As electronic devices continue to shrink in size and demand more power, finding a solution that can meet these requirements becomes crucial. This is where multi-layer ceramic capacitors (MLCCs) come into play.

MLCCs offer a compact form factor, high capacitance density, and robust performance, making them an ideal solution for a wide range of applications. According to Kings Research, the global Multi-Layer Ceramic Capacitor (MLCC) Market is estimated to reach a valuation of USD 27.10 billion by 2030. Let’s learn everything about it.

What is a Multi-Layer Ceramic Capacitor?

Multi-layer ceramic capacitors are a special kind of capacitor made up of several layers of ceramic material that serve as an insulator. Imagine them as a stack of individual capacitors packed into one unit. Inside, there are layers of metal electrodes separated by layers of ceramic. MLCCs function like a temporary reservoir for electrical charge, controlling the flow of current in a circuit and reducing interference between different parts.

The capacitance of an MLCC depends on how thick each layer of ceramic is and how many layers are stacked together. To create smaller capacitors with higher capacity, manufacturers use advanced techniques to make each layer thinner and stack more layers. This layered design allows MLCCs to offer high capacitance despite their compact size, making them perfect for tight-space applications.

Each MLCC is built with multiple layers of ceramic material sandwiched between conductive layers to form the capacitor plates. The ceramic typically contains a mix of finely ground materials like metal oxides, such as titanium dioxide, known for their high dielectric constant. Meanwhile, the conductive layers are made of metals like nickel, silver, or palladium.

How is a Multi-Layer Ceramic Capacitor Manufactured?

To craft multi-layer ceramic capacitors, a thin ceramic foil is first made by blending the ceramic powder with a binder and casting it into sheets. These sheets are then cut into uniform sizes and screen-printed with a layer of metal paste, forming the electrodes. Next, the sheets are stacked in layers, with the electrodes placed alternately and slightly offset to enable connection later on. This stacking process demands precise mechanical alignment, especially for hundreds of layers.

After stacking, the binder is burned away, and the stack is sintered at high temperatures, typically between 1,200 and 1,450°C, to achieve the desired crystalline structure and dielectric properties. Following sintering, the stack is cleaned and metalized on both ends to connect the inner electrodes in parallel, forming the capacitor's terminals.

MLCCs, lacking leads, are generally smaller and don't require through-hole access for mounting on a PCB. They're optimized for machine handling, making them cost-effective compared to their leaded counterparts.

These capacitors come in a wide range of capacitance values, spanning from 100 pF to 100 µF.

What are the Applications of MLCC?

Multi-layer ceramic capacitors are versatile components widely utilized across multiple industries. Here's a breakdown of their common applications:

  • Electronics: Found in everyday gadgets like smartphones, laptops, and TVs, MLCCs serve essential roles in decoupling, filtering, and power supply circuits.
  • Automotive: MLCCs are integral to automotive electronics, from engine control units to infotainment systems, providing reliable performance and aiding in system miniaturization.
  • Industrial Equipment: Used in motor control, power supplies, and lighting systems, MLCCs ensure stable operation in challenging industrial environments.
  • Telecommunications: MLCCs contribute to signal conditioning and impedance matching in telecommunications equipment, including base stations and routers.
  • Renewable Energy Systems: MLCCs are crucial components in solar inverters and wind turbines, providing energy storage and conditioning capabilities.
  • Medical Devices: MLCCs enable compact and reliable solutions in medical electronics, supporting patient monitoring systems and imaging equipment.
  • Aerospace and Defense: MLCCs deliver high reliability and performance in aerospace and defense applications, including avionics and radar systems.
  • Consumer Electronics: From gaming consoles to wearables, MLCCs aid in miniaturization and performance enhancements in consumer electronics products.

Different types of Multi-Layer Ceramic Capacitor

Here's an overview of common types of MLCC capacitors:

  • Class 1 MLCC: Known for their stability and precision, Class 1 MLCCs are ideal for applications demanding accurate capacitance values and low losses. They find extensive use in high-frequency circuits, filters, and timing circuits.
  • Class 2 MLCC: These capacitors boast higher permittivity, enabling greater capacitance values within a smaller footprint. Class 2 MLCCs are favored for applications requiring smaller capacitances, like bypass, coupling, and decoupling capacitors. They come in variants like X7R, C0G, and X7S, offering versatility in dielectric materials.
  • Y5V MLCC: Falling under Class 2 MLCCs, Y5V MLCCs offer a broad operating temperature range (-30 to +85 degrees Celsius), making them adaptable to various applications. However, they trade off stability and accuracy, with capacitance varying notably with temperature and voltage changes.
  • NP0/C0G MLCC: A subtype of Class 1 MLCCs, NP0/C0G MLCCs excel in stability across temperatures and minimal losses. They're perfect for applications demanding precise capacitance values and minimal temperature sensitivity.

Additionally, MLCCs come in various sizes denoted by a 4-digit code (e.g., 0201, 0402, 0603), where the first two digits represent length and the last two represent width. Common sizes include 0402, 0603, and 0805, catering to different space constraints and applications.

How Does a Multi-Layer Ceramic Capacitor Work?

Multi-layer ceramic capacitor operates by storing electrical charge between two conductive plates separated by a dielectric material. Within an MLCC, these plates consist of metal electrodes like silver or palladium, while the dielectric material is ceramic.

When a voltage is applied to the electrodes, an electric field develops within the dielectric material. This field polarizes the electrons, generating an electrical charge on the surface of the electrodes. The capacitance of an MLCC relies on factors such as the surface area of the electrodes, the distance between them, and the dielectric constant of the material. Ceramics typically have a higher dielectric constant compared to other materials, making them easier to polarize.

MLCCs are highly versatile and find use in a variety of electronic circuits, including filters, oscillators, and power supplies, where they serve to store and release electrical charge. Their low Equivalent Series Resistance (ESR) and high self-resonant frequency make them particularly suited for high-frequency circuits, enhancing performance and minimizing losses.

Do Multilayer Ceramic Capacitors Have Polarity?

Multi-layer ceramic capacitors can indeed be categorized into two distinct types: polar and non-polar. Non-polar MLCCs feature symmetrical construction, allowing them to be connected in either direction without any polarity concerns.

Conversely, polar MLCCs are intentionally designed with an asymmetrical structure, necessitating specific orientation during connection to ensure proper functionality. The positive & negative terminals of polar MLCCs are typically identified by markings such as letters, dots, stripes, or color codes. It's imperative to adhere to the correct polarity when connecting polar MLCCs, as reversing the orientation could result in capacitor failure or even an explosion. Additionally, soldering of polar MLCCs should be carried out with care to avoid overheating or damage.

Final Takeaway

Multi-layer ceramic capacitors are essential components in the field of electronics, finding applications in a wide range of industries including electronics, automotive, telecommunications, industrial equipment, renewable energy systems, medical devices, aerospace and defense, and consumer electronics. With their versatility and reliability, MLCCs continue to play a crucial role in driving technological advancements and innovation across industries.

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