Introduction:
Electronic products fill our work and life. The reasonable design of printed circuit board will directly affect the efficiency of electronic products. Whether the design of grounding, the electromagnetic compatibility, size of PCB board and the heat dissipation can meet the requirements of production and use is the focus of PCB design.
The Key Points of PCB Design:
Whether PCB design has good manufacturability is an important standard to measure PCB design. If you want to do this well, you should first grasp the following points.
1. Key Points of Grounding Design:
Ground system consists of four parts: analog ground, digital ground, enclosure ground and system ground. A proper grounding design can shield out most interference, which is very important in electrical equipment.
1) Choose a reasonable grounding method. Multi-point grounding and single-point grounding are two different ways of grounding, that is, we need to choose which one to use according to the actual situation. When the operating frequency of the equipment exceeds 10Mhz, the ground wire impedance value is relatively large because of the influence of electromagnetic radiation, which directly affects the normal operation of the equipment. At this time, we should choose the multi-point grounding mode to eliminate the adverse effects. When the operating frequency of the equipment is lower than 1Mhz, single point grounding mode should be electromagnetic circulation. When the operating frequency of the equipment is lower than 1-10mhz, the grounding mode shall be selected by referring to the circuit wavelength and ground line length. When the wavelength is less than 20 times of the ground line length, multi-point grounding shall be selected; otherwise, single point grounding shall be adopted.
2) Separate circuits of different properties. The circuit distribution on the circuit board is very complex. Fox example, there are maybe not only analog circuits but also digital circuits on the PCB board, the right way is to avoid the mutual interference is to separate them. The design of separate ground modes can effectively avoid the electromagnetic interference between each other.
3) The cross section of the ground wire should be wide and thick. The selection of grounding wire with cross section width of 3 mm or more can avoid the instability of grounding potential caused by the change of current and effectively improve the equipment's anti-noise performance. Therefore, the wide and thick grounding conductor should be selected as far as possible.
