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

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

PCBs are divided into single-layer boards and multi-layer boards, and four-layer boards are more commonly used multi-layer boards. So, what are the wiring rules for the PCB four-layer board?

  1 and 3 points or more. When designing the connection, let the line pass through each point in a regular manner, which is convenient for later testing, and the line length should be as short as possible.

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

  3. Adjacent layers are best not to be wired in parallel. Theoretically, there will be interference as long as the lines are parallel.

  4. Minimize bending wiring as much as possible to avoid electromagnetic radiation.

  5. When designing ground and power lines for multiple logic circuits, at least 10-15 mils.

  6. Try to connect the grounding polylines to increase the grounding area. Keep neat lines between lines.

  7. In the early stage of wiring, a space should be reserved for the later components to be evenly discharged to facilitate the later component installation, plug-in, and welding operations. 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 consider 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, 12/20mil pad. 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: Do not get too close to LCD components such as zebra strips.

  11. The vias should be painted 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 the antenna and other vulnerable areas. Place a ground pad under the crystal oscillator.

  15. Consider more methods such as reinforcement and hollowing out components to avoid excessive radiation sources.

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