For Electronic amateur, especially for beginners, knowing well for PCB layout is the first step for PCB design or product design. So there are few basic principles here for reference. A. Follow the layout principle of "big one before small one, difficult one before easy one", that is, important unit circuits and core components should be laid out in priority. B. The layout shall refer to the principle block diagram and arrange the main components according to the flow law of the main signal of the single board C. The layout shall meet the following requirements as far as possible: the total line shall be as short as possible, and the key signal line shall be the shortest; High voltage, the high current signal Completely separated from weak signals of low current and low voltage; Separation of analog signals from digital signals; High-frequency signal and low-frequency signal No separate; High-frequency components should be adequately spaced. **一 8 Tips for PCB Layout Details** 1. Meet the structural requirements, including the installation of the PCB board, the size and shape requirements of the PCB board, and the position of peripheral interfaces of the PCB board; 2. No layout and wiring in the forbidden area of the PCB board. Including plate edge, mounting hole or mounting seat hole, etc. Usually less than 1mm. Take 0.5mm as appropriate. 3. Meet the minimum requirements of the power supply channel, and the power supply channel shall not be affected by the over-dense layout of components. For example, the power supply and ground network will be broken due to the over-dense layout of filter capacitors, resulting in the discontinuity of signals and the incompleteness of the power supply and ground plane. 4. To meet the wiring channel requirements of key components, key signals, local over-density, and the whole board, the layout of key components and the routing planning of key signals need to be taken into account. 5. Meet the manufacturing ability requirements of PCB, and the spacing between components should be reasonable. For the convenience of welding and debugging, components of the same type should be arranged in the same direction as far as possible when space permits. 6. Meet the testability requirements of PCB, easy to detect, and repair. 7. On the premise of meeting the function and performance of the system, the components with high quality should be distributed evenly on the PCB as far as possible. 8. Make clear the air duct on the PCB, and arrange the upper and lower air tuyere reasonably according to the amount of heat dissipated by the device. ** [JLCPCB](JLCPCB) provide PCB prototype + SMT from $2, [$23 coupons]($23 coupons) for beginners now.** **二 8 tips for the basic order of the PCB layout** 1.Import CAD board and frame according to the structure drawing. Determine the external dimensions of the PCB board, window opening, etc. If the capacitor needs to be installed in the window lying down due to high speed, it should also be noted. 2. Set lamination parameters 3. Determine the location of components such as communication interface, positioning hole and installation hole according to the structure drawing. 4. Draw the forbidden wiring area 5. On the basis of the structural components already laid out, confirm the signal flow direction and the approximate location of key components Ensure that the peripheral circuit of key signal components adopts the mode of module layout, interactive placement in the schematic diagram and PCB design environment, and complete the layout of each module. 6, when the layout of the division of the function of each module accordingly, give priority to the clock system, control system, the layout of the power system, at the same time for primary and secondary power source planning and each functional module of the power supply to the nearest layout, and consider the power supply in power plane roughly split, with sufficient wiring for the interconnection between different devices. 7. Components with topology requirements shall be considered in the layout, and enough space shall be reserved for equinox winding of signals with length requirements. For example, in the layout of CPU and DDR, it is required that there should be no other component layout between DDR and CPU, and enough space should be left in the middle to facilitate the equinox winding of signals with timing requirements between CPU and DDR. 8. MARK points should be placed on the PCB if there is a Mosaic