Before designing a multi-layer PCB circuit board, the designer needs to first determine the circuit board structure used according to the scale of the circuit, the size of the circuit board and the requirements of electromagnetic compatibility (EMC), that is, to decide whether to use 4 layers, 6 layers, or More layers PCB board. After determining the number of layers, determine where to place the internal electrical layers and how to distribute the different signals on these layers. This is the choice of multi-layer PCB stack-up structure.
The stacked structure is an important factor affecting the EMC performance of the PCB board, and it is also an important means to suppress electromagnetic interference. This section will introduce the related content of the multi-layer PCB board stack-up structure. The selection of the number of layers and the principle of superposition There are many factors that need to be considered to determine the laminated structure of the multi-layer PCB board. In terms of wiring, the more layers, the better for wiring, but the cost and difficulty of making boards will also increase. For manufacturers, whether the laminate structure is symmetrical or not is the focus that needs to be paid attention to when manufacturing PCB boards, so the selection of the number of layers needs to consider the needs of various aspects to achieve the best balance. For experienced designers, after the completion of After the pre-layout of the components, a key analysis will be carried out on the routing bottleneck of the PCB.
Finally, combine other EDA tools to analyze the wiring density of the circuit board; then combine the number and types of signal lines with special wiring requirements, such as differential lines, sensitive signal lines, etc., to determine the number of layers of the signal layer; then according to the type of power supply, isolation and Anti-interference requirements to determine the number of inner layers. In this way, the number of layers of the entire circuit board is basically determined.