You should know the basic knowledge and role of copper coating in PCB

There are several reasons why copper should be coated.

1. EMC
The copper coating for a large area of ground or power supply, it will play a shielding role, and some special ground, such as PGND plays a protective role.

2. PCB process requirements
Generally in order to ensure the electroplating effect, or for the lamination process, substrate is not deformed. The PCB with less wiring pattern, it also needs to coat copper.

3. The requirement of signal integrity

One of the great benefits of copper coating is to reduce the impedance of ground wire. (A large part of the so-called anti-interference is the reduction of ground impedance.)There are a lot of peak pulse current in digital circuits, so reducing ground impedance is even more necessary. It is generally believed that for a circuit composed entirely of digital devices, a large area of copper should be coated. And for an analog circuit, the ground loop formed by copper coating will cause electromagnetic coupling interference rather than gain (except for high-frequency circuits). Therefore, it is not a circuit that must be copper coated. (BTW, the performance of copper grid is better than that of the whole block.).

The significance of the copper coating lies in:
1. Copper coating and ground connected, so the loop area can be reduced.
2. A large area of copper coating is equivalent to reducing the resistance of the ground wire, reducing the press drop. On these two points, both digital and analog ground should be copper-coated to increase anti-interference capability. And at high frequencies, copper-coating for digital ground and analog ground should be done separately, and then connect them with a single point. This single point can be wound several circles with a wire on a magnetic ring and then connected. However, if the frequency is not too high, or if the working conditions of the instrument are not bad, it can be relatively relaxed. The crystal can be counted as a high-frequency emitter in the circuit. You can lay copper around it and then ground the housing of crystal. This would be better.

What is the difference between the copper block and a grid?
1) From the point of view of PCB processing, PCB with grid copper is less productive than solid copper in mass production.
2) From the welding process, if going the wave soldering, a large area of copper coated PCB board may warp, green oil (solder mask) will even bubble. From this point of view, the heat dissipation of the grid is better.
3) From the point of view of EMC, high frequency circuits with high anti-interference requirements, grid copper clad is often used. Low frequency circuits with high current etc., solid copper clad is commonly used.