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PCB copper processing
PCB copper processing
Copper cladding is to use the free space on the PCB as a reference plane and then fill it with solid copper. These copper areas are also called copper filling. The significance of copper plating is to reduce the impedance of the ground wire and improve the anti-interference ability; reduce the voltage drop and improve the efficiency of the power supply; and connect to the ground wire to reduce the loop area. If the PCB has a lot of ground, such as SGND, AGND, GND, etc., how to cover copper? My approach is to use the most important "ground" as the reference to independently cover the copper, Separating the digital ground from the analog ground is not much to say. At the same time, before copper cladding, first thicken the corresponding power connections: V5.0V, V3.6V, V3.3V (powered by SD card), and so on. In this way, a plurality of differently deformed structures are formed.
There are several issues that need to be dealt with in copper clad: first, single-point connection at different places, and second, copper clad near the crystal. The crystal in the circuit is a high-frequency emission source. The method is to deposit copper around the crystal, and then separate the casing Ground. The third is the isolated island (dead zone) problem. If you think it is very large, then it will not take much to define a land via to add it.
In addition, whether large-area copper is better than grid copper is not good. Why? Large-area copper, if the wave soldering, the board may tilt up, or even blister. From this point, the heat dissipation of the grid is better. It is usually a multi-purpose grid with high requirements for high-frequency circuits to resist interference, and low-frequency circuits with large currents.
Added:
数字 In digital circuits, especially in circuits with MCUs, the function of copper is to reduce the impedance of the entire ground plane. A more specific processing method is generally used in this way: each core module (also digital circuits) will be zoned copper when it is allowed, and then each wire is connected with a wire. The purpose of this is also In order to reduce the influence between each level of circuit.
For mixed circuits of digital circuits and analog circuits, the independent routing of the ground wire, and the summary to the power filter capacitor at the end will not say much, everyone is clear. However, there is one point: the distribution of the ground wire in the analog circuit can not be simply laid on a copper sheet, because the analog circuit pays attention to the interaction between the front and back stages, and the analog ground also requires a single point ground, so can you put the Laminating copper to simulate the ground also needs to be handled according to the actual situation.
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