The general principles designers need to follow in the PCB layout process are as follows.

(1) Components are best placed on one side. If you need to place components on both sides, place pin-type components on the bottom layer (Bottom Layer), components are best placed on one side. It may cause the circuit board to be difficult to place and not conducive to soldering, so it is best to place only chip components on the bottom layer (bottom layer) in the bottom layer, similar to the common component layout method on the computer graphics PCB board . When placed on one side, it is only necessary to make a silk screen layer on one side of the circuit board, which is convenient for reducing costs.

(2) Reasonably arrange the position and direction of interface components. Generally speaking, as the connection between the circuit board and the outside world (power supply, signal line), generally speaking, as the circuit board and the outside world (power supply, signal line), the connector components are usually arranged on the edge of the circuit board, such as Serial and parallel ports. If it is placed in the center of the circuit board, it is obviously not conducive to wiring. The connector components are usually arranged on the edge of the circuit board, such as serial ports and parallel ports. It may also be impossible to connect due to the obstruction of other components. In addition, pay attention to the direction of the interface when placing the interface, so that the connection cable can also pay attention to the direction of the interface when placing the interface, and also pay attention to the direction of the interface when placing the interface, smoothly lead out, away from the circuit board. Lead out smoothly, away from the circuit board. After the interface is placed, the String of interface components should be used to clearly indicate the type of interface; for the power interface, the voltage level should be marked to prevent the circuit board from being burned due to incorrect wiring. For the power supply interface, the voltage level should be marked to prevent the circuit board from being burned due to incorrect wiring.

(3) It is better to have a wide electrical isolation zone between high-voltage components and low-voltage components. That is to say, don't make the voltage level greatly different) It is better to have a wide electrical isolation band between high-voltage components and low-voltage components. Do not put components with very different voltage levels together, and components together. This is not only beneficial for electrical insulation, but also for signal isolation and anti-interference.

(4) Components with close electrical connections are best placed together. This is the modular layout idea. ) Components with close electrical connections are best placed together. This is the modular layout idea.

(5) For components that are prone to noise, such as high-frequency components such as clock generators and crystal oscillators, they should be placed as much as possible when placed) For components that are prone to noise, such as high-frequency components such as clock generators and crystals, Clock input. High-current circuits and switching circuits are also prone to noise, and are placed close to the clock input of the CPU. High-current circuits and switching circuits are also susceptible to noise. These components or modules should also be kept away from high-speed signal circuits such as logic control circuits and storage circuits during layout, or modules should also be kept away from high-speed signal circuits such as logic control circuits and storage circuits. If possible, try to use the control board combined with the power board, and use the interface to connect to improve the overall anti-interference ability and working reliability of the circuit board.

(6) Place decoupling capacitors and filter capacitors around the power supply and the chip as much as possible. The arrangement of the decoupling capacitor and filter capacitor is to improve the circuit board electricity. Place the decoupling capacitor and filter capacitor as much as possible around the power supply and the chip. The quality of the source is an important measure to improve the anti-interference ability. In practical applications, the traces, pin connections and wiring of the printed circuit board are in practical applications, and the traces, pin connections and wiring of the printed circuit board are likely to bring more Large parasitic inductances cause high-frequency ripples and glitches in the power supply and signal waveforms, and placing them between the power supply and ground may cause large parasitic inductances, resulting in high-frequency ripples and Glitch, a 0.1 F decoupling capacitor can effectively filter out these high-frequency ripples and glitches. If a chip capacitor is used on the circuit board, if a chip capacitor is used on the circuit board, or if a chip capacitor is used on the circuit board, place the chip capacitor close to the power pins of the component. Place the chip capacitor close to the power supply pin of the component. For the power conversion chip or the power input terminal, it is better to arrange a 10 F or larger capacitor to further improve the power quality.

(7) The number of components should be arranged close to the border of the component, the size is uniform, the direction is neat, and it is not heavy with the components, vias and pads. The direction is neat and folded. The first pin of the component or connector indicates the direction; the positive and negative signs should be clearly marked on the PCB and are not allowed to be covered; power conversion components (inverter, linear conversion power supply and switching power supply) power conversion components (For example, DC / DC converter, linear conversion power supply and switching power supply) There should be sufficient heat dissipation space and installation space, and enough welding space should be left in the periphery. There is enough welding space around the periphery.