The PCB circuit board is divided into many layers. What are the skills of the PCB multilayer board wiring of more than four layers? The following Fast turn pcb Int’l Co. will introduce to you, I hope to help you a certain amount.
1. Try not to put wires between pins, especially between and around integrated circuit pins.
2. When connecting more than 3 points, try to let the line pass through the points in order to facilitate the test. The length of the line should be as short as possible.
3. The wiring of the PCB multilayer board should be as straight as possible, or a 45-degree broken line to prevent the generation of electromagnetic radiation.
4. The lines between different layers should not be parallel as much as possible to avoid the formation of actual capacitance.
5. The ground wire and power wire should be at least 10-15mil (for logic circuit).
6. Try to make the poly-laying lines connected together to increase the grounding area. Keep the lines as neat as possible.
7. Pay attention to the uniform discharge of components for installation, plug-in and welding operations. The text is placed on the current character layer, the orientation is reasonable, pay attention to the orientation, prevent being blocked, and easy to produce.
8. Consider the structure of component discharge. The positive and negative poles of the chip components should be marked in the package and finally marked to prevent space conflicts.
9. Now the printed board can be used for 4-5mil wiring, but generally for 6mil line width, 8mil line spacing, 12 / 20mil pad. The wiring should consider the influence of sinking current, etc.
10. The functional block components should be placed together as much as possible, and the components near the LCD such as zebra strips should not be too close.
11. Green oil should be applied to the vias (set to a negative value).
12. It is best not to place pads, over-empty, etc. under the battery holder, and the size of PAD and VIL is reasonable.
13. After the wiring is completed, carefully check whether each link (including NETLABLE) is really connected (available lighting method).
14. Oscillation circuit components should be as close as possible to the IC, and the oscillation circuit should be as far away as possible from the antenna and other easily disturbed areas. Place the ground pad under the crystal.
15. Consider multiple methods such as PCB multi-layer board reinforcement, hollowing out and placing components to prevent excessive radiation sources.