Views:4 Author:Site Editor Publish Time: 2018-04-24 Origin:Site
The stability and capacity accuracy of the chip capacitor are related to the dielectric materials used. The general flake capacitor includes five kinds of dielectric: C0G, X7R, X5R, Y5V, Z5U, among which the first three are commonly used.
C0G patch capacitor belongs to class I high frequency capacitor. It is a kind of high frequency capacitor with COG/NPO as class I dielectric. Its capacitance is very stable and almost does not change with the change of temperature, voltage and time. It is especially suitable for high-frequency electronic circuits such as oscillations and timing circuits. Capacitor is one of the most stable capacitors with the most stable capacitance and dielectric loss. When the temperature is from -55 ℃ to + 125 ℃, the capacity changes to 0 ±30PPm/ ℃, and the change of capacitance with frequency is less than ±0. 3 Δ C.
The drift or hysteresis of the capacitance is less than ±0.05, which can be ignored when the capacitance is larger than ±2%. The variation of typical capacity relative to service life is less than ±0.1%. The capacitance and dielectric loss of NPO capacitors vary with the frequency in different packaging forms. The large package size is better than the small package size frequency characteristics. The capacity accuracy is mainly ±5%, and when the capacity is lower than 10PF, three kinds of accuracy can be selected: B (±0.1PF), C (±0.25PF), D (±0.5PF).
X7R and X5R patch capacitors belong to class II low-frequency capacitors, and their capacitance capacity is relatively stable. The difference between them is that the maximum operating temperature is 125 ℃ for the former and 85 ℃ for the latter. Suitable for various filtering and coupling circuits. The capacitance of X7R dielectric patch is usually gray. Its temperature coefficient is ±15, capacitance is relatively stable, suitable for various bypass, coupling, filter circuits, its capacity accuracy is mainly K (±10), in special cases, can provide J (±5) precision products. Y5V dielectric patch capacitors belong to type II low-frequency capacitors, whose temperature coefficient is: + 30 -80. The capacitance varies greatly by temperature, voltage and time, and is generally only suitable for various filter circuits.
Its capacity accuracy is mainly Z + 80-20, but also can choose ±20% precision products. The capacity varies from 22% to -82% and the dielectric loss is 5% in the range of working temperature from -30 ℃ to 85 ℃. Due to the high dielectric constant of Y5V patch capacitor, it is allowed to produce capacitors up to 100 μ F in small physical size, which can be used as a substitute for tantalum capacitors in some circuit environments. The capacitance of Z5U dielectric is between X _ 7R and Y _ 5V in terms of capacitance stability, and its working temperature is + 30 ~ 80 ℃ in the range of + 10 ℃ and + 85 ℃.