What are the wiring rules for four-layer PCB boards?

PCB is divided into single-layer board and multi-layer board, and four-layer board is the most used multi-layer board. So, what are the wiring rules for the four-layer PCB?

1. When designing the connection of more than 3 points, let the line pass through each point in sequence, which is convenient for later testing, and the length of the line should be shortened as much as possible.

2. Avoid wiring around the pins, and pay special attention to reducing the wiring design between and around the pins of the integrated circuit.

3. It is best not to route parallel lines between adjacent layers. In theory, as long as the lines are parallel, there will be interference.

4. Minimize bending wiring to avoid electromagnetic radiation.

5. For multi-logic circuits, the ground wire and power wire should be designed at least 10-15mil.

6. Try to connect the multi-segment lines of the floor as much as possible to increase the grounding area. Lines should be kept neatly between lines.

7. In the early stage of wiring, a space position for the distribution of components in the later stage should be reserved for the installation, plug-in, and welding operations of the later components. The text is arranged in the current character layer, and the position is reasonable to avoid being blocked.

8. The placement and installation of components should be considered from the sense of space. The positive and negative poles of SMT components should be marked on the package and at the end.

9. At present, the printed circuit board can be used for 4-5mil wiring, but usually 6mil line width, 8mil line spacing, and 12/20mil pads. The influence of multiple factors such as sink current should be considered when wiring.

10. Put the functional block components together as much as possible to facilitate later inspection. Special reminder: components near the LCD such as zebra strips should not be too close.

11. The vias should be coated with green oil.

12. It is best not to place pads, vias, etc. under the battery base to ensure the firmness of multiple uses.

13. After the wiring is completed, carefully check whether each connection is really connected (the lighting method can be used).

14. The oscillating circuit components should be as close to the IC chip as possible, and as far away as possible from areas susceptible to interference such as antennas. The ground pad should be placed under the crystal.

15. Consider various methods such as reinforcement and hollowing out components to avoid too many radiation sources.

The above is the wiring rules of the four-layer PCB board, do you understand it?

If you want to know more about it, send email to lisa.wang@pcb-hero.com