Chip capacitor is a kind of capacitor material. SMD capacitor full name: multilayer (accumulation layer, laminated) chip ceramic capacitors, also known as chip capacitors, chip capacitance. Chip capacitor has two ways to express, one is the inch unit to express, and one is the millimeter unit to express.
Chip Capacitors
Chip multilayer ceramic dielectric capacitor (mlcc) is called chip capacitor for short, which consists of ceramic dielectric film with printed electrodes (inner electrode) stacked together in a misaligned manner, and then sintered at high temperature to form a ceramic chip, and then sealed with metal layer (outer electrode) at both ends of the chip to form a monolithic structure, so it is also called monolithic capacitor.
The structure of multilayer ceramic chip capacitor consists of three main parts: ceramic dielectric, metal inner electrode, and metal outer electrode. The multilayer ceramic chip capacitor is a multilayer stacked structure, which is simply a parallel connection of several simple parallel plate capacitors.
Role of chip capacitor
Bypass
A bypass capacitor is an energy storage device that provides energy to the local device, which homogenizes the output of the regulator and reduces the load demand. Like small rechargeable batteries, bypass capacitors are capable of being charged and discharged to the device. To minimize impedance, the bypass capacitor should be placed as close as possible to the supply power pin and ground pin of the load device. This is a good way to prevent ground potential elevation and noise caused by excessive input values. The ground potential is the voltage drop at the ground connection when passing through a high current burr.
Decoupling
Decoupling, also known as decoupling. In terms of the circuit, it can always be distinguished between the source that is driven and the load that is driven. If the load capacitance is relatively large, the driving circuit has to charge and discharge the capacitor to complete the signal jump, and the current is larger when the rising edge is steeper, so that the driven current will absorb a large supply current, and due to the inductance in the circuit, the resistance (especially the inductance on the chip pin, which will generate a bounce), this current is actually a noise relative to the normal situation, which will affect the front stage This is the so-called “coupling”.
The decoupling capacitor is to play a “battery” role, to meet the changes in the current of the drive circuit, to avoid mutual coupling interference.
Combining bypass capacitor and decoupling capacitor will be easier to understand. The bypass capacitor is actually decoupling, but the bypass capacitor generally refers to the high frequency bypass, which is to improve a low impedance drain path for high frequency switching noise. High-frequency bypass capacitor is generally small, according to the resonant frequency is generally taken 0.1μF, 0.01μF, etc.; while the capacity of the decoupling capacitor is generally larger, may be 10μF or larger, according to the distribution parameters in the circuit, and the size of the change in the drive current to determine. Bypass is to filter out the interference in the input signal, while decoupling is to filter out the interference in the output signal to prevent the interference signal from returning to the power supply. This should be the essential difference between them.
쿠캅 슈퍼 커패시터

쿠캅 슈퍼 커패시터

Filtering
Theoretically (i.e. assuming that the capacitor is pure), the larger the capacitance, the lower the impedance and the higher the frequency through which it passes. But in practice, most capacitors over 1μF are electrolytic capacitors, which have a large inductive component, so the impedance will increase instead after the frequency is high. Sometimes you can see a large capacitance electrolytic capacitor in parallel with a small capacitor, when the large capacitor through the low frequency, the small capacitor through the high frequency. The role of capacitance is to pass high resistance low, through high frequency resistance low frequency. The larger the capacitance, the easier it is to pass the low frequency. Specifically used in filtering, large capacitor (1000μF) filter low frequency, small capacitor (20pF) filter high frequency. Some users have imaginatively compared the filter capacitor to a “water pond”. Since the voltage at both ends of the capacitor does not change suddenly, it can be seen that the higher the signal frequency, the greater the attenuation. It converts the change of voltage into the change of current, and the higher the frequency, the higher the peak current, thus buffering the voltage. Filtering is the process of charging, discharging.
Energy storage
An energy storage capacitor collects charge through a rectifier and transfers the stored energy through the converter leads to the output of the power supply. Aluminum electrolytic capacitors with voltage ratings of 40 to 450 VDC and capacitance values between 220 and 150,000 μF (such as B43504 or B43505 from EPCOS) are more commonly used. Depending on the requirements of different power supplies, the devices are sometimes connected in series, parallel or a combination thereof. For power supplies with a power level of more than 10KW, larger can-shaped screw terminal capacitors are usually used.
SMD capacitor usage
Mainly to remove the crosstalk of various high frequency signals generated by the chip itself to other chips, so that each chip module can work normally without interference. In the high frequency electronic oscillation circuit, the chip capacitor and the crystal oscillator and other components together form an oscillation circuit to provide the required clock frequency to various circuits.
Chip capacitors include chip ceramic capacitors, chip tantalum capacitors, and chip aluminum electrolytic capacitors. Chip ceramic capacitors have no polarity and small capacity, and can generally withstand very high temperature and voltage, and are often used for high frequency filtering. Ceramic capacitors look a bit like chip resistors, but there is no number representing the capacity size on chip capacitors. The characteristics of chip capacitor are long life, high temperature resistance, high accuracy, excellent performance of high frequency filtering, but the capacity is smaller and more expensive than aluminum capacitor, and the ability of voltage and current resistance is relatively weak. It is used in low frequency filtering circuit with small capacity.
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