Multilayer ceramic capacitors are widely used in portable products, but in recent years, technological advancements in digital products have put forward new requirements for them. For example, mobile phones require higher transmission rates and higher performance; The baseband processor requires high speed and low voltage; LCD modules require low thickness (0.5mm) and large capacity capacitors. The harshness of the automotive environment has special requirements for multilayer ceramic capacitors: firstly, they must be resistant to high temperatures, and the multilayer ceramic capacitors placed in them must be able to meet a working temperature of 150℃; Secondly, short-circuit failure protection design is required on the battery circuit.
That is to say, miniaturization, high speed and performance, high temperature resistance, and high reliability have become the key characteristics of ceramic capacitors.
The capacity of ceramic capacitors varies with the change of DC bias voltage. The DC bias voltage reduces the dielectric constant, so it is necessary to reduce the dependence of dielectric constant on voltage from the material aspect and optimize the DC bias voltage characteristics.
The X7R (X5R) class multilayer ceramic capacitors are commonly used in applications, with a capacity mainly concentrated above 1000pF. The main performance indicator of this type of capacitor is equivalent series resistance (ESR), which is particularly prominent in low-power applications such as high ripple current power decoupling, filtering, and low-frequency signal coupling circuits.
