Product description  
MLCC overlapping layer -type capacitor  
Generally, ceramic patch capacitance refers to MLCC, that is, multi -layer ceramic film capacitors.  
The conventional patch capacitance is divided into COG (NPO), X7R, Y5V, and its pin packaging is 0201,0402,0603.0805.1206,1210,1825,2225.  
Multi -layer ceramic capacitors (MLCC) are layered by parallel ceramic materials and electrode materials.  
 
Capacitor function:  
1) bypass  
Wingle capacitors are energy storage devices that provide energy for local devices. It can uniformly output the voltage regulator and reduce load demand. Just like a small -scale rechargeable battery, bypass capacitors can be charged and discharge to the device. In order to minimize the impedance, the bypass capacitance should be as close to the power supply pipe and ground pipe foot of the load device as much as possible. This can prevent the ground potential and noise from being raised and noisy caused by excessive input values. The ground power level is the voltage drop when the ground connection is through the large current burrs.  
2) Define  
Definement, also known as decoupling. From the circuit, it can always be distinguished into the source of the driver and the driving load. If the load capacitance is relatively large, the driving circuit must charge and discharge the capacitance to complete the jump of the signal. When the rising edge is steep, the current is relatively large, so that the drive current will absorb a large power current. Due to the circuit, due to the circuit The inductance, resistance (especially the inductance on the chip's feet, will cause a rebound). This current is actually a kind of noise compared to normal, which will affect the normal work of the previous stage. This is the so -called "coupling" Essence  
The decoupling capacitor is a "battery" role to meet the changes of the drive circuit current and avoid coupling interference between each other. Combining bypass capacitors and decoupling capacitors will be easier to understand. The barrier capacitance is actually decoupled, but bypass capacitors generally refer to high -frequency bypass, that is, to increase the low impedance prevention pathway to high -frequency switch noise. High -frequency bypass capacitors are generally relatively small, and 0.1 μF, 0.01 μF, etc. are generally small according to the resonance frequency. The capacity of the decoupled capacitance is generally large, which may be 10 μF or larger. to make sure. The bypass is to use the interference in the input signal as the filtering object, and the decoupling is to use the interference of the output signal as the filtering object to prevent the interference signal from returning the power supply. This should be their essential difference.  
3) Filter  
Theoretically (that is, the capacitor is a pure capacitor), the larger the capacitance, the smaller the impedance, and the higher the frequency of passing. However, in fact, more than 1 μF capacitors are electrolytic capacitors, which have a large inductance ingredient, so the impedance will increase after the frequency is high. Sometimes I see a large electrolytic capacitor with a large electrolytic capacitance in parallel. At this time, the large capacitance is low -frequency, and the small capacitance is high -frequency. The role of capacitance is to have low high resistance and low frequency blocking low frequency. The larger the capacitance, the easier it is to pass. Specific in filtering, large capacitors (1000 μF) filter low frequency, small capacitors (20PF) filtering high frequency. Some netizens have compared the filter capacitance to "ponds". Because the voltage ends of the capacitor will not change, it can be seen that the higher the signal frequency, the larger the decay. It can be said that the capacitor is like a pond, which will not cause changes in water volume due to the addition of several drops of water. It converts the change of voltage into changes in current. The higher the frequency, the larger the peak current, which cushion the voltage. Filter is the process of charging and discharge.  
4) Energy storage  
Energy storage capacitors collect charge through a rectifier, and transmit the stored energy to the output end of the power supply through the transform leader. The voltage rated value is 40 to 450VDC, and the capacitance value of the aluminum electrolyte capacitor (such as the B43504 or B43505 of EPCOS Company) is more commonly used. According to different power supply requirements, the device sometimes uses the form of series, parallel or its combination. For power levels with a power level of more than 10kW, a larger canal spiral terminal capacitor is usually used.