With new materials and mixtures as well as different designs in terms of arrangement and structure, suppliers of ceramic capacitors have created numerous optimized components in recent years. As a result, there is an array of specific capacitors to choose from for varying applications and functions with special requirements. These differ with regard to their properties, size, or design, thereby meeting a wide range of requirements. The best-known variants include, for example, the high-frequency (HF), high-quality (HiQ), radio-frequency (RF), microwave, low-inductance, and low-loss types, capacitors with internal copper electrodes or end terminations for conductive bonding, and so-called X2Y versions.
Special Types for Specific Applications
In addition to the aforesaid types, other special capacitor variants are also available, such as variable capacitors, which offer voltage-controllable and thus variable capacitance by utilizing the DC bias response (Fig. 1).
TDK’s CeraLink® capacitors are specially designed for high currents, as they exhibit an increase in capacitance over the applied voltage across wide areas (Fig. 2).
Also less known are the 3D silicon capacitors. They use the third dimension to substantially increase the capacitor surface and thus its capacitance. Murata, for instance, offers a 0402 size model, measuring just 100 µm in height, which delivers 100 nF. The 3D capacitors respond similarly to NP0 types, and are particularly suitable for HF applications up to 110 GHz and high-temperature applications up to 250 °C (Fig. 3).
When Supply Security Matters
All these special types have the following in common: They are particularly optimized for specific requirements or applications but are thus also frequently referred to as single-source components. This means that there is no alternative, which often leads to significant procurement difficulties when supplies are short and allocation periods long.
This problem arises not as much with basically standard MLCCs. Here, too, different variants are available, e.g. with varying C-value tolerances, voltages, or temperature ranges, with special terminations (soft termination, silver-palladium), or as commercial or automotive grade components. However, many models match in design, size, ceramic type, etc., so there are usually several alternatives to choose from for these capacitors (so-called CV products) also from many different suppliers. In Rutronik's portfolio are SEMCO (Samsung Electro-Mechanics), Yageo, KEMET, KyoceraAVX, Murata, TDK, Vishay and Samwha.
Smart Parameter Setting for Alternatives
Progressing digitization makes it easier to handle multiple variants, but at the same time it also ensures that the selection is only made exactly according to the defined parameters. It is often the case, for example, that a capacitor with a tolerance of 20% (code letter M) has been defined, but when searching for alternatives, components with the better tolerance value of 10% are not accepted because the designation fails to match.
Rutronik has created the table as an orientation aid to facilitate the search for alternatives. It indicates in which directions an exchange is uncritical and when this exchange is in fact possible, but individual parameters must be checked first.
In order to obtain a cost-effective and flexible result for redesigns and new developments, it is also advisable to focus on the smallest possible design and to define the parameters, e.g. voltage, tolerance, but also the type of ceramic (which also defines the temperature range), on the basis of the actual requirements. This avoids oversizing, which also limits the choice of alternatives. However, when searching for alternatives, the components with better specifications must then also be approved. If these tips are followed, users will benefit from the diversity of variants, especially in times of short supply.
For more information and a direct ordering option, please visit our e-commerce platform at www.rutronik24.com.
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