PCB high-speed 4 layers above layout experience
1. 3 points above the connection, as far as possible through the line in order to facilitate testing, the length of the line as short as possible.
2. Try not to put the pins between them, especially between and around the IC pins.
3. As far as possible not between the different layers of parallel lines, so as to avoid the formation of the actual capacitance.
4. Wiring as straight as possible, or 45 degree polylines, to avoid electromagnetic radiation.
6. Try to make the floor polyline connected together to increase the ground area. As far as possible tidy lines and lines.
7. Note that the components are evenly discharged for installation
8. Components to consider more than the structure of emissions, SMD components have positive and negative should be marked in the package and the final to avoid space conflicts.
9. At present the PCB can be used for 4-5mil cabling, but usually 6mil line width, 8mil line spacing, 12 / 20mil pad. Wiring should consider the impact of irrigation current.
10. Function block components as much as possible together, zebra strips and other components near the LCD can not be too close.
11. Vias to be painted green (set to negative double).
12. Battery holder is best not to place the pad
13. After wiring is completed, carefully check each connection (including NETLABLE) is really connected (available lighting method).
14. Oscillation circuit components as close as possible to IC, oscillation circuit as far as possible away from the antenna susceptible area. Under the crystal to put ground pad.
15. Consider more reinforcement