Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

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How to strengthen the ability of anti-interference in PCB design

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How to strengthen the ability of anti-interference in PCB design | 20 November, 2014

To get the best performance of electronic circuits, components and circuit board supports circuit components and devices in electronic products. Even if the circuit principle diagram design is correct, the printed circuit board is designed improperly, which will have a negative impact on the reliability of electronic products. When the printed circuit board is designed, we should pay attention to the correct method used to be in accordance with the general principles of PCB design. And conforming to the layout and arrangement of wire anti-interference design requirements part is very important. In order to design good quality, low cost of the PCB, should follow the general principle of the following: Layout

First, consider the PCB size. When the PCB size is too large, the printed lines will be long, the resistance will also increase, which will decrease the ability of anti noise and increase the cost; when it is too small, then the heat is not good, and the adjacent lines are susceptible to interference. It is better to first determine the PCB size, and then the special element position. Finally, to carry out the layout of all the components of the circuit according to the functional unit circuit.

In determining the special element position must comply with the following principles:

1* as far as possible to shorten the connection between high frequency components, trying to reduce the electromagnetic interference between their distribution parameters . Components that are susceptible to interfer are not too close together, and the input and output elements should be kept away from each other.

2* There may be a higher potential difference between certain components or wire, so the distance between them should be increased, so as to avoid accidental short circuit discharge leads. Components with high voltage should be arranged in the debugging place where the hand can not touch.

3* Components whose weight is oover 15g should be fixed with the bracket before welded. Those big, heavy and with much calorific value should not be installed on the printed circuit board, but in the chassis backplane of the machine, and shall consider the problem of heat dissipation. The thermosensitive element should be far away from the heating element.

4* The layout for those adjustable components like the potentiometer, adjustable inductance coil, variable capacitor, a micro switch etc should consider the requirements of the structure of the entire machine. If it is the inner machine adjustment, they should be put on a certain place on the printed circuit board where it is convenient to adjust; if the outer adjustment, the location shall be compatible with the adjusting knob on the panel of the case position.

5* The position occupied by the printed circuit board positioning hole and the fixed bracket should be left.

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How to strengthen the ability of anti-interference in PCB design | 20 November, 2014

PCB layout of the circuit components, to meet the requirements of anti interference design:

1* arranged for each functional circuit unit in accordance with the circuit flow position, the layout of the signal for circulation, and make the signal as much as possible to maintain consistent direction.

2* with the core elements of each functional circuit as the center, around it to layout. Components should be uniform, neat, compact arrangement in PCB. Minimize and shorten the lead between each component and connection.

3* circuit in high frequency, to consider the distributed parameter between the components. General circuit should as far as possible components arranged in parallel. In this way, not only beautiful, but also welding easy, easy batch production.

4* is located on the edge of the circuit board components, away from the edge of the Board shall be not less than 2mm. The optimum shape of the circuit board is rectangular. The length and width of double 3:2 or 4:3. Circuit board size greater than 200 x 150mm, consideration should be given to the mechanical strength of the circuit board by.

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