PCB high speed board more than 4 layers of wiring experience:
1. If the line is connected at more than 3 points, try to let the line pass through each point in turn, which is convenient for testing, and the line length should be as short as possible.
2. Try not to put wires between pins, especially between and around integrated circuit pins.
3. The lines between different layers should not be parallel as far as possible to avoid the formation of actual capacitance.
4. The wiring should be straight line or 45 degree broken line to avoid electromagnetic radiation.
5. At least 10-15mil for ground wire and power line (for logic circuit).
6. Try to connect the multi sense lines together to increase the grounding area. The lines should be as neat as possible.
7. Pay attention to the uniform discharge of components for installation, plug-in and welding. The text is placed in the current character layer, the position is reasonable, pay attention to the direction, avoid being blocked, easy to produce.
8. The structure should be taken into account when the components are discharged. The positive and negative electrodes of the chip components should be marked at the end of the package to avoid space conflict.
9. At present, printed circuit board can be used for 4-5mil wiring, but usually 6mil line width, 8mil line spacing, 12 / 20MIL pad. The influence of pouring current should be considered in wiring.
10. Function block components should be put together as far as possible, and components near LCD such as zebra stripes should not be too close to each other.
11. The via should be painted green (set to negative one time value).
12. Pad and VIL should not be placed under the battery holder. Pad and VIL are reasonable in size.
13. After wiring, carefully check whether each connection (including netlable) is really connected (lighting method can be used).
14. The components of the oscillation circuit should be close to the IC as far as possible, and the oscillation circuit should be far away from the antenna and other vulnerable areas. Put the ground pad under the crystal oscillator.
15. In order to avoid too many radiation sources, many ways should be taken into consideration, such as reinforcement, hollowing out components and so on.