Do you know whether isolated copper should be removed in PCB design? There are numerous issues that require attention in PCB design techniques, and the compatibility of various components, as well as finished product issues, are all important factors to be considered. The topic of our discussion today is whether isolated copper should be removed during PCB design.
Do you know whether isolated copper should be removed in PCB design? There are numerous issues that require attention in PCB design techniques, and the compatibility of various components, as well as finished product issues, are all important factors to be considered. The topic of our discussion today is whether isolated copper should be removed during PCB design.
Some people hold the opinion that isolated copper should be removed, for the following main reasons:
- It will cause EMI issues.
- Removing it can enhance the anti-interference capability of the circuit.
- Dead copper serves no practical purpose.
Others believe that isolated copper should be retained, with the following main reasons:
- Removing it may leave large blank areas on the board, which is aesthetically unpleasing.
- It increases the mechanical performance of the board and avoids bending caused by uneven stress.
First, we do not recommend retaining ungrounded isolated copper (islands), because such islands will form an antenna effect. If the surrounding traces have high radiation intensity, the isolated copper will amplify the surrounding radiation intensity; it will also act as a receiving antenna, introducing electromagnetic interference to the surrounding traces.
Second, we can remove some small-area isolated islands. If we wish to retain the copper pour, the isolated islands should be well connected to the GND plane through ground vias to form a shielding structure.
Third, in high-frequency scenarios, the distributed capacitance of the wiring on the printed circuit board will come into play. When the length of the wiring exceeds 1/20 of the wavelength corresponding to the noise frequency, an antenna effect will occur, and noise will be radiated outward through the wiring. If there is poorly grounded copper pour in the PCB, the copper pour will become a tool for noise propagation. Therefore, in high-frequency circuit design, never assume that a certain point of the ground line is grounded just because it is connected to the ground at one location. Vias must be added to the wiring at a spacing of less than λ/20 to achieve "good grounding" with the ground plane of the multilayer board. When copper pour is properly handled, it not only increases the current-carrying capacity, but also plays the dual role of shielding interference.
Fourth, retaining the copper pour of isolated islands with ground vias added can not only play the role of shielding interference, but also effectively prevent PCB deformation. The above is the analysis of dead copper removal in PCB design, and we hope it will be helpful to you.
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