PCB board (printed circuit board) is divided into single-sided, double-layer and multi-layer. The number of layers of multilayer board is not limited. At present, there are 100 layers of PCB, including four layers and six layers.

The simple four layer board adds a power layer and a layer on the basis of the Top Layer and Bottom Layer, which greatly solves the electromagnetic interference problem, improves the reliability of the system, and can also improve the wiring rate and reduce the area of the PCB board.

The number of layers of the multilayer board is very flexible, and the designer can reasonably set it according to the actual situation. So, what is the delamination principle of pcb multilayer board? The setting of each layer shall meet the following requirements:

1. The power supply plane shall be close to the ground plane, closely coupled with the ground plane, and arranged below the ground plane. Below the element layer is the ground plane, which provides the device shielding layer and the reference layer of the top layer wiring;

2. The signal layer shall be adjacent to the internal electrical layer and not directly adjacent to other signal layers. All signal layers shall be as close to the ground plane as possible;

3. Isolate digital circuit and analog circuit. If possible, lay analog signal lines and digital signal lines in layers and take shielding measures; If they need to be laid on the same signal layer, isolation belt and ground wire shall be used to reduce interference; The power ground wire and ground wire of analog circuit and digital circuit shall be isolated from each other and shall not be mixed.

4. When designing multilayer boards, each layer should be symmetrical, and even copper layers are preferred. If it is asymmetrical, it is easy to cause distortion.