Principles of PCB layout design

                                                                 Principles of PCB layout design

For large Components such as ICs, BGA and non-positioning connectors, 50 to 100 mil grid can be used for layout. For small compnents such as resistors, capacitors and inductors, 25 mil grids can be used for layout. Using grid points for layout can make the components to be more aligned and beautiful.

1. Under normal situation, all components should be placed on the same side of the PCB. Only when the top side components are too dense, then the components which with low heat generation will be placed on the bottom side, such as the SMT resistors, SMT capacitors and chip ICs.

2. Under the premise of ensuring electrical performance and in order to be neat and beautiful, the components should be placed on the grid and arranged parallel or perpendicular to each other. Under normal situation, components are not allowed to overlap. Components should be evenly distributed and uniform on the entire surface.

3. The minimum spacing between adjacent pads on different components of the PCB should be more than 1MM.

4. The space from the component to PCB outline should be more than 2MM. The shape of the PCB should be try to designed as a rectangle, and the aspect ratio is 3:2 or 4:3. When the PCB dimension is larger than 200MM*150MM, we also need to consider whether the mechanical strength of the PCB can meet the requirements.

5. Center on the core components of each functional unit, and then other components are arranged around this core component. Components should be evenly, neatly and compactly arranged on the PCB to minimize and shorten lead wire between components.