Copper coating conditions for PCB circuit boards

　　(1) For boards that require strict impedance control, do not apply copper as it can affect impedance control due to the distributed capacitance between the copper and the wiring;

　　(2) For devices and PCBs with high wiring density in the upper and lower layers, copper plating is not necessary. At this time, the copper plating is fragmented and basically ineffective, and it is difficult to ensure good grounding;

　　(3) For single-sided and double-sided power boards, it is important to ensure that the power cord is connected to the ground wire and not to use copper plating. If copper plating is used, it will be difficult to ensure a proper circuit;

　　(4) If it is a PCB with more than 4 layers (excluding 4 layers), and the second layer and the second to last layer are complete ground planes, copper plating is not necessary. However, if the device and wiring density of the upper and lower layers are small, copper plating is better;

　　(5) If the impedance requirement is not strict for PCBs with less than 4 layers, copper can be applied when there is space, because the distance between layers of PCBs with less than 4 layers is far (>10 mil). At this time, copper can be applied with a wire spacing of about 7 mil, which can have a certain reflow effect;

　　(6) The flat layer inside the multi-layer digital board should be firmly used instead of copper plating. Firstly, if the copper plating is a grid, the impedance is very high. Secondly, if the wiring is not connected, lazy people will directly lay the signal lines on this layer. There are too many drawbacks, not to mention;

　　(7) If the inner layers are all single strip lines, the layers with less wiring do not need to be coated with copper. If there are double strip lines, copper can be coated. At this time, attention should be paid to the good grounding of the inner layer copper coating. The premise of this solution is that there is no requirement for impedance control of the single board.