A ceramic capacitor is a fixed-value capacitor in which ceramic material acts ceramic capacitor datasheet pdf the dielectric. It is constructed of two or more alternating layers of ceramic and a metal layer acting as the electrodes.
Class 1 ceramic capacitors offer high stability and low losses for resonant circuit applications. Class 2 ceramic capacitors offer high volumetric efficiency for buffer, by-pass, and coupling applications. EMI suppression, as feed-through capacitors and in larger dimensions as power capacitors for transmitters. Since the beginning the study of electricity non conductive materials like glass, porcelain, paper and mica have been used as insulators. Even in the early years of Marconi’s wireless transmitting apparatus, porcelain capacitors were used for high voltage and high frequency application in the transmitters. On the receiver side, the smaller mica capacitors were used for resonant circuits.
Mica dielectric capacitors were invented in 1909 by William Dubilier. Mica is a natural material and not available in unlimited quantities. So in the mid-1920s the deficiency of mica in Germany and the experience in porcelain—a special class of ceramic—led in Germany to the first capacitors using ceramic as dielectric, founding a new family of ceramic capacitors. But this paraelectric dielectric had relatively low permittivity so that only small capacitance values could be realized. The expanding market of radios in the 1930s and 1940s create a demand for higher capacitance values but below electrolytic capacitors for HF decoupling applications. The higher permittivity resulted in much higher capacitance values, but this was coupled with relatively unstable electrical parameters. Therefore, these ceramic capacitors only could replace the commonly used mica capacitors for applications where stability was less important.
Smaller dimensions, as compared to the mica capacitors, lower production costs and independence from mica availability accelerated their acceptance. The fast-growing broadcasting industry after the Second World War drove deeper understanding of the crystallography, phase transitions and the chemical and mechanical optimization of the ceramic materials. Through the complex mixture of different basic materials, the electrical properties of ceramic capacitors can be precisely adjusted. War from the 1950s through the 1970s was a ceramic tube covered with tin or silver on both the inside and outside surface. It included relatively long terminals forming, together with resistors and other components, a tangle of open circuit wiring. EIA class IV capacitors, were developed using doped ferroelectric ceramics. Because this doped material was not suitable to produce multilayers, they were replaced decades later by Y5V class 2 capacitors.
The early style of the ceramic disc capacitor could be more cheaply produced than the common ceramic tube capacitors in the 1950s and 1970s. An American company in the midst of the Apollo program, launched in 1961, pioneered the stacking of multiple discs to create a monolithic block. As of 2012, more than 1012 MLCCs were manufactured each year. New developments in ceramic materials have been made with anti-ferroelectric ceramics. The different ceramic materials used for ceramic capacitors, paraelectric or ferroelectric ceramics, influences the electrical characteristics of the capacitors. Higher capacitance values for ceramic capacitors can be attained by using mixtures of ferroelectric materials like barium titanate together with specific oxides.
An alternative to X2Y capacitors may be a “three — these different electrical characteristics of ceramic capacitors requires to group them into “application classes”. Class 3 barrier layer or semiconductive ceramic capacitors have very high permittivity – the expanding market of radios in the 1930s and 1940s create a demand for higher capacitance values but below electrolytic capacitors for HF decoupling applications. The different ceramic materials used for ceramic capacitors, this code is international and in common use. Which summarizes all ohmic losses of the capacitor, class 1 capacitors have capacitance values in the lower range.
These dielectric materials have much higher permittivities, but at the same time their capacitance value are more or less nonlinear over the temperature range, and losses at high frequencies are much higher. These different electrical characteristics of ceramic capacitors requires to group them into “application classes”. The definitions of the application classes given in the two standards are different. In many parts very similar to the IEC standard, the EIA RS-198 defines four application classes for ceramic capacitors. The different class numbers within both standards are the reason for a lot of misunderstandings interpreting the class descriptions in the datasheets of many manufacturers.
The EIA ceased operations on February 11, 2011, but the former sectors continue to serve international standardization organizations. In the following, the definitions of the IEC standard will be preferred and in important cases compared with the definitions of the EIA standard. Class 1 ceramic capacitors are accurate, temperature-compensating capacitors. They offer the most stable voltage, temperature, and to some extent, frequency. They have the lowest losses and therefore are especially suited for resonant circuit applications where stability is essential or where a precisely defined temperature coefficient is required, for example in compensating temperature effects for a circuit. Zinc, Zirconium, Niobium, Magnesium, Tantalum, Cobalt and Strontium, which are necessary to achieve the capacitor’s desired linear characteristics.