Talk about the principle of PCB layout design should follow

Talk about PCB layout design should follow the principle: PCB circuit board is the electronic components of the circuit components and devices even if the circuit schematic design is correct, improper printed circuit board design, electronic products will also adversely affect the reliability. When designing printed circuit boards, care should be taken to use the correct method to comply with the general principles of PCB design and to meet the requirements of anti-jamming design.

First, the PCB layout design should follow the principle:

First, to consider the size of the PCB size.PCB size is too large, the printed line length, impedance increases, anti-noise capacity decreased, the cost increases; too small, the heat is not good, and adjacent lines vulnerable to interference in determining the printed circuit board Size, and then determine the location of special components. Finally, according to the functional unit of the circuit, all the components of the circuit layout.

The following principles apply when determining the location of special components:

As shown in Figure 1, as far as possible to shorten the connection between high-frequency components, try to reduce their distribution parameters and mutual electromagnetic interference. The components that are susceptible to interference can not be too close to each other, and the input and output components should be kept as far away as possible.

2, some components or wires may have a higher potential difference between, should increase the distance between them, so as not to lead to accidental discharge short circuit. Components with high voltage should be arranged as far as possible in the debugging hand difficult to reach the place.

3, the weight of more than 15 grams of components, should be fixed with a bracket, and then welding. Those large and heavy, more heat and more components, should not be installed on the printed circuit board, but should be installed in the machine chassis chassis, and should consider the cooling problem. The thermal element should be away from the heating element.

As shown in Figure 4, for the potentiometer, adjustable inductance coil, variable capacitors, micro switches and other adjustable components of the layout should consider the structural requirements of the machine if the machine should be placed on the printed circuit board to facilitate the adjustment Place; if the machine outside the adjustment, its position and adjust the knob on the chassis panel to adapt to the location.

5, should be set aside the PCB positioning holes and fixed stent occupied by the location.

Second, the circuit components of the PCB layout, to meet the anti-jamming design requirements:

As shown in Fig. 1, the position of each functional circuit unit is arranged in accordance with the flow of the circuit so that the layout facilitates the flow of the signal and keeps the signal as uniform as possible.

2, to each functional circuit of the core components as the center, around it to the layout. Components should be even, neat and compactly arranged on the PCB. Minimize and shorten the lead and connection between the components.

3, in the high frequency of the circuit, to consider the distribution of components between the parameters. The general circuit should arrange the components as parallel as possible. This is not only beautiful, but easy to install and easy to mass production.

As shown in Figure 4, the circuit board at the edge of the edge of the board, from the edge of the circuit board is generally not less than 2 mm The best shape of the circuit board is rectangular rectangle length of 3: 2 or 4: 3 circuit board size greater than 200 × 150, should consider the mechanical strength of the circuit board.