Ceramic Capacitors
Semec Ceramic capacitors are available with High Voltage type, low voltage Ceramic Disc type, Radial Multilayer and Chip MLCC. Voltage range from 16V, 25V, 50V, 63V, 100V, 500V, 1KV, 2KV and max reach 50KV for high Voltage Ceramic cap.
Different material ( NPO, X7R, Y5V) make ceramic capacitor used in different application, which are suitable for low-lost circuits, timing and tuning applications etc.
Bulk pack, Ammo pack are common package for Through-hold type and Chip MLCC is Tape & Reel pack.
Y1/ Y2 class safety standard Ceramic capacitor are available with voltage of 400VAC and 250VAC.
Ceramic Capacitors List
| Series | SCH | SCJ | SCK | SCL | SCY |
|---|---|---|---|---|---|
| Feature | High Voltage Ceramic Capacitor | Ceramic Disc Capacitor | Radial Multilayer Ceramic Capacitor | Chip Multilayer Ceramic Capacitor | Y1Y2 Safety standard recognized Ceramic Capacitor |
| Capacitance range | 100pF to 0.01uF | 0.5pF to 0.01uF | 0.5pF to 22uF | 0.5pF to 10uF | 100pF to 0.01uF |
| Rated Voltage | DC 1KV ~ 50KV | DC50V, 500V | DC 16V, 25V, 50V, 63V, 100V | DC 16V, 25V, 50V | 250VAC, 400VAC |
| Capacitance Tolerance | ±5%, ±10%, ±20%, +80-20% | ±0.25pF, ±0.5pF ,±5%, ±10%, ±20%, +80-20% | ±0.25pF, ±0.5pF ,±5%, ±10%, ±20%, +80-20% | ±0.25pF, ±0.5pF ,±5%, ±10%, ±20%, +80-20% | ±10%, ±20%, +80-20% |
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About Ceramic Capacitors
Ceramic capacitors have a dielectric made of ceramic materials. General specifications include configuration, capacitance type, and technology. There are two basic configurations for ceramic capacitors: leaded and surface mount. Leaded ceramic capacitors have leads for connections to circuits. Surface mount capacitors or chip capacitors do not. Ceramic capacitor technologies are categorized as monolithic, multilayer, or wound. Monolithic components use a dielectric made of a single layer. Multilayer devices are made of many layers and are small in size. They provide excellent temperature stability and frequency characteristics. Wound capacitors are built by winding foils, sometimes by hand. In terms of technology, there are two choices: fixed and variable. Fixed ceramic capacitors have a nonadjustable capacitance value. With variable ceramic capacitors, specific capacitance values are set with a potentiometer.
Ceramic capacitors differ in terms of electrostatic material, the insulation between the plates of a multilayer capacitor. Ceramic COG (NPO) capacitors have a high Q, low K, temperature-compensated dielectric and stable electrical properties under varying voltage, temperature, frequency and time. They are suitable for low-lost circuits and for timing and tuning applications. Ceramic X7R (BX) capacitors have moderate K values and are temperature-stable. They exhibit moderate changes in electrical properties under conditions of changing temperature, voltage, and frequency. Ceramic Z5U capacitors are Class III devices with a dielectric that exhibits a maximum capacitance change of +22% - 56% over an operating temperature range of +10 °C to + 85 °C. Ceramic capacitors with other types of electrostatic material are also available.
Selecting ceramic capacitors requires an analysis of performance specifications and packaging specifications. Products also differ in terms of features and compliance with Restriction of Hazardous Substances (RoHS). Performance specifications for ceramic capacitors include capacitance range, capacitance tolerance, DC rated voltage range (WVDC), test voltage, dissipation factor, insulation resistance, and equivalent series resistance (ESR). There are three categories of packaging specifications: lead or termination type, mounting style, and packing method. Choices for lead type include surface mount technology (SMT), axial, radial, flying, tab, screw, gull-wing, and J-leads. There are five mounting styles: through-hole technology (THT), surface mount technology (SMT), bolt, bracket, and pole. Tape reel, tray or rail, and shipping tube or stick magazine are common packing methods for ceramic capacitors.
Ceramic Capacitors Information
In electronics ceramic capacitor is a capacitor constructed of alternating layers of metal and ceramic, with the ceramic material acting as the dielectric. The temperature coefficient depends on whether the dielectric is Class 1 or Class 2. A ceramic capacitor (especially the class 2) often has high dissipation factor, high frequency coefficient of dissipation.
Ceramic Capacitors Construction
A ceramic capacitor is a two-terminal, non-polar device. The classical ceramic capacitor is the "disc capacitor". This device pre-dates the transistor and was used extensively in vacuum-tube equipment (e.g., radio receivers) from about 1930 through the 1950s, and in discrete transistor equipment from the 1950s through the 1980s. As of 2007, ceramic disc capacitors are in widespread use in electronic equipment, providing high capacity & small size at low price compared to other low value capacitor types.
Ceramic capacitors come in various shapes and styles, including:
- disc, resin coated, with through-hole leads
- multilayer rectangular block, surface mount
- bare leadless disc, sits in a slot in the PCB and is soldered in place, used for UHF applications>
- tube shape, not popular now
HF use Ceramic Capacitors
Ceramic capacitors are suitable for moderately high-frequency work (into the high hundreds of megahertz range, or, with great care, into the low gigahertz range), as modern ceramic caps are fairly non-inductive compared to the other major classes of capacitors (film and electrolytic). Capacitor technologies with higher self-resonant frequencies tend to be expensive and esoteric (typically, mica or glass capacitors).
Sample self-resonant frequencies for one set of C0G and one set of X7R ceramic capacitors are:
| 10pF | 100pF | 1nF | 10nF | 100nF | 1uF | |
| C0G (Class 1) | 1550MHz | 460MHz | 160MHz | 55MHz | ||
| X7R (Class 2) | 190MHz | 56MHz | 22MHz | 10MHz |
Classes of ceramic capacitors
Three classes of ceramic capacitors are commonly available:
Class I capacitors: accurate, temperature-compensating capacitors. They are the most stable over voltage, temperature, and to some extent, frequency. They also have the lowest losses. On the other hand, they have the lowest volumetric efficiency. A typical class I capacitor will have a temperature coefficient of 30ppm/C. This will typically be fairly linear with temperature. These also allow for high Q filters -- a typical class I capacitor will have a dissipation factor of 0.15%. Very high accuracy (~1%) class I capacitors are available (typical ones will be 5% or 10%). The highest accuracy class 1 capacitors are designated C0G or NP0
Class II capacitors: better volumetric efficiency, but lower accuracy and stability. A typical class II capacitor may change capacitance by 15% over a -55C to 85C temperature range. A typical class II capacitor will have a dissipation factor of 2.5%. It will have average to poor accuracy (from 10% down to +20/-80%).
Class III capacitors: high volumetric efficiency, but poor accuracy and stability. A typical class III capacitor will change capacitance by -22% to +56% over a temperature range of 10C-55C. It will have a dissipation factor of 4%. It will have fairly poor accuracy (commonly, 20%, or +80/-20%). These are typically used as decoupling or in other power supply applications.
At one point, Class IV capacitors were also available, with worse electrical characteristics than Class III, but even better volumetric efficiency. They are now rather rare and considered obsolete, as modern multilayer ceramics can offer better performance in a compact package.
These correspond roughly to low K, medium K, and high K. Note that none of the classes are "better" than any others -- the relative performance depends on application. Class I capacitors are physically larger than class III capacitors, and for bypassing and other non-filtering applications, the accuracy, stability, and loss factor may be unimportant, while cost and volumetric efficiency may be. As such, Class I capacitors are primarily used in filtering applications, where the main competition is from film capacitors in low frequency applications, and more esoteric capacitors in RF applications. Class III capacitors are typically used in power supply applications. Traditionally, they had no competition in this niche, as they were limited to small sizes. As ceramic technology has improved, ceramic capacitors are now commonly available in values of up to 100uF, and they are increasingly starting to compete with electrolytic capacitors, where ceramics offer much better electrical performance at prices that, while still much higher than electrolytic, are becoming increasingly reasonable as the technology improves.