Basic principles of PCB stacking design: for PCB manufacturers, there are many factors that need to be considered in PCB stacking scheme. As CAD engineers, they often pay attention to as many wiring layers as possible to achieve the convenience of later wiring. Of course, signal quality and EMC are also the focus of CAD engineers; For cost engineers, the idea is: can there be two layers less Whether the laminated structure is symmetrical is its focus.
What a brilliant CAD engineer needs to do is: how to comprehensively consider the opinions of all parties to achieve the best combination point.
The following is the stack design reference summarized by edadoc experts according to their many years of experience in PCB design of communication products, which can be shared with you. Basic principles of PCB stacking design after completing the layout (or pre layout), the CAD Engineer focuses on the analysis of the wiring bottle diameter of the board, and then determines the number of wiring layers in combination with the report parameters of EDA software on wiring density (pin / rat) and the number and type of signals with special wiring requirements such as differential line, sensitive signal line and special topology; Then, according to the type and distribution of power supply and ground of the single board, the number of signal layers with special wiring requirements, and the performance index requirements and cost bearing capacity of the single board, determine the number of power supply and ground layers of the single board and their relative arrangement position with the signal layer.
General principles of veneer layer layout:
A) The layer adjacent to the element surface is the ground plane, providing the device shielding layer and providing the return plane for the top-level wiring;
B) All signal layers shall be adjacent to the ground plane as far as possible (ensure that the key signal layer is adjacent to the ground plane);
C) The main power supply shall be adjacent to it as much as possible;
D) Try to avoid two signal layers directly adjacent;
E) Give consideration to the symmetry of laminated structure. When setting specific PCB layers, we should flexibly grasp the above principles, and determine the layer layout according to the actual needs of single boards. We should not copy mechanically.
The recommended layer layout schemes of common boards are given below for your reference (not limited to these, various combinations can be derived according to the actual situation). Note: S – signal layer p – power layer G – group layer