2. Avoid direct signal coupling, which will affect the signal quality.
3. When multiple module circuits are placed on the same PCB, digital circuits and analog circuits, high-speed and low-speed circuits should be laid out separately.
4. Avoid mutual interference among digital circuits, analog circuits, high-speed circuits and low-speed circuits.
5. When there are high, medium and low speed circuits on the circuit board at the same time, the layout principle shown below should be followed.
6. Avoid high-frequency circuit noise radiating outward through the interface.
7. Energy storage and high-frequency filter capacitors should be placed near unit circuits or devices with large current changes (such as input and output terminals of power modules, fans and relays).
8. The existence of energy storage capacitor can reduce the loop area of large current loop.
9. The filter circuit of the power input port of the circuit board should be placed close to the interface.
10. Avoid coupling the filtered lines again.
1 1. On the PCB board, the filtering, protection and isolation devices of the interface circuit should be placed close to the interface.
12. It can effectively achieve the effects of protection, filtration and isolation.
13. Strong radiation devices such as crystals, crystal oscillators, relays and switching power supplies should be at least 1000mil away from the single board interface connector.
14. Direct radiation interference or coupling out current on the output cable.
15. Each filter capacitor used for IC filtering should be as close as possible to the power supply pin of the chip.
16. The closer the capacitor is to the pin, the smaller the high-frequency loop area and the smaller the radiation.