Pinsheng Electronics Co.,Ltd
The so-called copper coating is to use the unused space on the PCB as a datum, and then fill it with solid copper, which is also known as copper pouring.The significance of copper coating is to reduce the ground line impedance and improve the anti-interference ability.Reduce pressure drop and improve power efficiency;It is connected to the ground wire and can reduce the loop area.Also out to keep as much as possible when PCB welding deformation, the purpose of most of the PCB manufacturer will ask PCB designer in open areas of the PCB who or ground grid, copper clad if processes improper, it will not reward, copper clad is "not do more harm than good" or "do more harm than good"?
Under the condition of high frequency is known to all, on the printed circuit board wiring capacitance will work, when the length is more than 1/20 of the noise frequency corresponding wavelength, can produce the antenna effect, the noise will launch out through wiring, if there are bad grounding copper clad in the PCB, copper clad became the tool of transmission noise, therefore, in the high frequency circuit, don't believe that somewhere in the ground after the, this is the "ground", must be less than the spacing of lambda / 20, punch a hole in the cabling, and multilayer ground plane "well grounded".If copper is treated properly, the copper coating not only increases the current, but also plays a dual role of shielding interference.
There are two basic ways of covering copper, namely large areas of copper and copper, and it is often asked whether it is good to cover large areas of copper or copper, so it is not easy to generalize.Why is that?Large area covering copper, has the double action of increasing current and shielding, but large area covering copper, if the wave crest welding, the board may become up, even can bubble.So large copper clad, general will also open a few slots, alleviate copper foil blister, pure copper mesh is main or shielding effect, increase the current function is reduced, from the perspective of heat dissipation, the grid is good, it reduces the heating surface of copper) and have the effect of a certain electromagnetic shielding.But it should be pointed out that, the grid is made by alternating direction of running, we know for circuit line width for the work frequency of the circuit board has its corresponding "electricity" length of (actual size divided by the working frequency of the corresponding digital frequency, concrete books), when the working frequency is not high, perhaps the role of the grid lines is not obvious, once the electrical length and working frequency matching, is very bad, you will find that the circuit won't work properly, emission signal interference system work everywhere.So for the colleagues who use the grid, my suggestion is to choose according to the design of the circuit board, not to hold a kind of things.Therefore, high frequency circuit to resist interference requires high multi-purpose grid, low frequency circuit with large current circuit and so on commonly used complete copper.
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