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Shenzhen PCB

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what principles should follow when design PCB layout???

PCB circuit boards are the support of circuit components and devices in electronic products. Even if the circuit schematic design is correct, printed circuit board design is improper, but also the reliability of electronic products have a negative impact. 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, consider the PCB size. PCB size is too large, the printed line length, impedance increases, anti-noise ability to decline, the cost increases; too small, the heat is not good, and adjacent lines vulnerable to interference. After determining the printed circuit board size, determine the location of the 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:

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 15g of the 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.

4, for the potentiometer, adjustable inductance coil, variable capacitor, micro switch and other adjustable components of the layout should consider the structural requirements of the machine. If the machine is adjusted, it should be placed on the printed circuit board to facilitate the adjustment of the place; if the machine outside the adjustment, its position to 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:

1, according to the circuit of the process of arranging the location of the various functional circuit unit, so that the layout of the signal flow, and make the signal as much as possible to maintain a consistent direction.

2, to each functional circuit of the core comonents 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.

4, located in the edge of the circuit board components, from the edge of the circuit board is generally not less than 2mm. The best shape of the circuit board is rectangular. Length and width are 3: 2 or 4: 3. When the circuit board size is greater than 200 × 150mm, the mechanical strength of the circuit board should be taken into account.

from AKEN.ZHANG

senior manager of CHINA PCB [email protected]