Ceramic Capacitors

Dearborn Electronics Inc., an Exxelia company, is a world leader in ceramic capacitor technology with extensive experience in design, development, and manufacturing of a wide range of ceramic capacitors. Multi-layer ceramic capacitors are made in the form of monolithic blocks with interleaved metal electrodes that are alternately exposed on opposite sides of the package. Advanced design, analysis, and test techniques are used to verify and guarantee the quality of materials and products.

Applications for ceramic capacitors include aeronautics, space, military, and railways (power supply, voltage multipliers, radars). Specialty ceramic capacitors have exceptional high temperature capability (up to 220 µF), which enables performance in downhole oil exploration. High voltage capability (up to 37,000 VDC) provides superior performance in voltage multipliers for medical devices. Any application requiring low losses, precision, stability or low inductance can find capacitor solutions in a wide variety of ceramic designs and packages customized to suit the requirements.

How is Ceramic used in Capacitors?

Ceramic chips are created with binders and solvents added to a specified ceramic powder. The slurry created is dried, forming a sheet or tape of ceramic material. Metal powder is mixed with solvents and additional ceramic material to create a liquid electrode. The liquid is then printed onto the ceramic layer. Layers of the ceramic sheets are stacked and laminated to form a solid structure.

The solid structure is cut into the desired size. Once cutting is complete, the assembly must be kiln fired. The temperature used in the firing process is critical in determining the capacitor’s characteristics. The process is similar for disc and chip styles. Disc capacitors use long leads to mount through circuit boards. Chips use surface mount technology.

Silver versus Base Metals

Electrodes used in ceramic capacitors come under the categories of precious metals or base metals. Silver is used for manufacturing capacitors for higher voltage ratings, 500V and above. Copper and nickel are used for applications under 500 V.

Dearborn Distributors can provide you with chip style ceramic capacitors that handle up to 1kV in operating ranges of -55° C to 125° C. Standard tolerances include +/- 5, +/- 10 and +/- 20 percent. For stringent applications, tolerances can be as low as +/- 0.25 pF.

Multilayer Ceramic Capacitors

Our multilayer ceramic capacitor (MLCC) is a chip capacitor manufactured with layers of ceramic material and metal. The alternating layers can be built up to the desired capacitance range. The dielectric thickness determines the voltage rating. The capacitance is determined by multiplying the number of layers by the amount of active area and then the dielectric constant for the material. This number is then divided by the dielectric thickness. The active area is the overlap between the electrodes.

A capacitor with a thicker dielectric layer handles higher voltages than one with a thinner layer. Inversely, the thinner dielectric will have a higher capacitance rating. The MLCC design provides a significant space-saving advantage over other capacitor styles. Dearborn Sales Representatives are available to help you cross-reference your current capacitors with our product line.

Do I need Class 1 or Class 2 fixed-value Capacitors?

A Class 1 ceramic capacitor is the best choice for applications that demand low losses and high stability. This style provides a reliable capacitance within the designated range of frequency, temperature and voltage. Class 2 series offer higher capacitance, but have wider fluctuations. The thermal stability varies by +/- 15 percent; these should be used in applications that do not require a continual exact capacitance.
Class 1 feed through capacitors offer high frequency noise reduction, and are excellent for use in microwave transmission, medical applications and DC supply and signal lines. Feed through design uses an axial-style lead for connections.

High Temperature, High Voltage and High Frequency Capacitors

High temperature ceramics can handle up to 200 C, with voltages ranges from 50 volts up to 3,000 volts. High frequency ceramic capacitors are available up to 120 uF. High voltage applications in ceramic styles are available in 100 to 10kV, 200 to 10kV, 200 to 5kV and 200 to 10kV. Power capacitors are much larger in size than their disc or chip counterparts. They are also designed to provide a direct connection to higher voltage supplies.

Dearborn Electronics can create the capacitor you need for your application. Simply send us your drawing or request a quote. Dearborn International Sales Representatives are available for non-U.S. customers.