PCB design is a very complex job with many rules. However, there are some common design rules. If you get the hang of it, you can do the job well. Let the engineer elaborate on the common design rules for PCB circuit boards:

1.3W rule.

The 3W rule is that the distance between lines must be kept 3 times the line width, that is, the usual 3H; H refers to the width of lines and lines. Theoretically, when the line center distance is 3 times, 70% of the electric field between lines can remain undisturbed, which is often referred to as the 3W rule.

2. Component layout rules.

The layout of components is very important and directly affects the performance of the product. Attention must be paid to the ordering, which is divided into the following points:

First, the schematic is the foundation. The schematic diagram must be repeatedly considered to optimize the design, and follow the rules of first big and then small, first difficult and then easy. The layout of critical cells and core electronic components should be limited.

The second is to reserve debugging positions for small components. Circuits with the same structure and similar structure should be distributed as symmetrically and evenly as possible.

Third, pay attention to the direction of the problem. Electronic components of the same type should be designed and arranged in the X-axis or Y-direction. For special elements, especially heating elements, they should be finely and evenly distributed.

Fourth, the layout should be as short as possible, with the shortest key signal lines.

3. Wiring rules.

High-speed signals, small touch signals, key signals such as synchronization signals and clock signals must be routed first. Start wiring from the most densely connected area on the board, and follow the rules of first big and then small, first difficult and then easy.

4.20H Rules.

Refers to the distance that the power layer shrinks 20h relative to the ground layer, that is, to ensure that the edge of the power plane is at least 20 times smaller than the edge of the 0V plane between the two planes. This is to suppress the radiation effect of the edge.