PCB design requires different grid settings at different stages. In the layout phase, large grid points can be used for device layout.
For large devices such as ICs and non-positioning connectors, 50 to 100 mil grid precision can be used for layout. For passive small devices such as resistors, capacitors and inductors, 25 mil grids can be used for layout. The accuracy of the large grid points facilitates the aesthetics of the alignment and layout of the device.
PCB design layout rules:
1.Under normal circumstances, all components should be placed on the same side of the board. Only when the top components are too dense, some devices with limited height and low heat can be placed, such as chip resistors, chip capacitors, and stickers. The chip IC is placed on the lower layer.
2. Under the premise of ensuring electrical performance, the components should be placed on the grid and arranged parallel or perpendicular to each other in order to be neat and beautiful. Under normal circumstances, the components are not allowed to overlap; the components are arranged in a compact manner, and the components should be on the entire layout. Uniform distribution, uniform density.
3. The minimum spacing between adjacent components of the board on the board should be less than 1MM.
4. The edge of the board is generally not less than 2MM. The optimal shape of the board is rectangular, and the aspect ratio is 3:2 or 4:3. When the board scale is larger than 200MM by 150MM, the board should be considered. Mechanical strength.
In the layout design of the PCB, the unit of the circuit board should be analyzed, and the layout design according to the function should be carried out. When all the components of the circuit are laid out, the following principles must be met:
1.Arrange the position of each functional circuit unit according to the flow of the circuit, so that the layout facilitates signal circulation and keeps the signal as consistent as possible.
2. Centering on the core components of each functional unit and surrounding it. Components should be evenly, integrally and compactly arranged on the PCB to minimize and shorten leads and connections between components.