What is the copper pour in the PCB?
If the PCB has many grounds, such as SGND, AGND, GND, etc., according to the position of the PCB board, the main "ground" is used as a reference to independently pour copper, that is, connect the grounds together. .
There are generally several reasons for copper paving.
1. EMC. For large-area ground or power supply copper, it will play a shielding role, and some special grounds, such as PGND, play a protective role.
2. PCB process requirements. Generally, in order to ensure the electroplating effect, or the lamination is not deformed, copper is laid on the PCB layer with less wiring.
What is copper paving? Analysis of the effect of copper paving in PCB
3. The signal integrity is required to provide a complete return path for high-frequency digital signals and reduce the wiring of the DC network. Of course, there are also reasons such as heat dissipation, special device installation requires copper and so on. There are generally several reasons for copper paving.
1. EMC. For large-area ground or power supply copper, it will play a shielding role, and some special grounds, such as PGND, play a protective role.
2. PCB process requirements. Generally, in order to ensure the electroplating effect, or the lamination is not deformed, copper is laid on the PCB layer with less wiring.
3. The signal integrity is required to provide a complete return path for high-frequency digital signals and reduce the wiring of the DC network. Of course, there are also reasons such as heat dissipation, special device installation requires copper and so on.
One. One of the major benefits of copper paving is to reduce the impedance of the ground wire (a large part of the so-called anti-interference is also brought about by the reduction of the ground wire impedance). There are a large number of spike currents in the digital circuit, so it is more necessary to reduce the ground wire impedance. It is generally believed that a large area of ground should be laid for circuits composed entirely of digital devices, while for analog circuits, the ground loop formed by laying copper will cause electromagnetic coupling interference to outweigh the gain (except for the High frequency board). Therefore, it is not that all circuits require ordinary copper (BTW: the performance of mesh copper paving is better than that of a whole block)
2. The significance of circuit copper paving lies in: 1. The copper paving is connected to the ground wire, which can reduce the loop area. 2. The large-area copper paving is equivalent to reducing the resistance of the ground wire and reducing the voltage drop from these two points. In other words, whether it is digital ground or analog ground, copper should be laid to increase the anti-interference ability, and at high frequency, the digital ground and analog ground should be separated to spread copper, and then connected with a single point. This single point can Use a wire to wind a few turns on a magnetic ring, and then connect. However, if the frequency is not too high, or the working conditions of the instrument are not bad, it can be relatively relaxed. The crystal oscillator can be counted as a Microwave radio frequency board in the circuit. You can spread copper around and ground the crystal oscillator's shell, which will be better.
3. What is the difference between a copper block and a grid? To analyze in detail, there are about 3 functions: 1 beautiful 2 suppressing noise 3 in order to reduce high-frequency interference (the reason on the High frequency board).
