The copper clad of PCB board is a crucial step in PCB design, with certain technical content. So how to do the design work of this link, our senior engineers have discussed and summarized the following points.
Introduction of Copper Cladding:
The so-called copper cladding is to use the unused space on the PCB as a reference surface and then fill it with solid copper. These copper areas are also called copper filling. The significance of copper coating is to reduce the impedance of the ground wire and improve the anti-interference ability, reduce the voltage drop and improve the efficiency of the power supply. Connecting with the ground wire can also reduce the loop area. Also for the purpose of making the PCB as not deformed as possible when soldering, most PCB manufacturers will also require PCB designers to fill the open area of the PCB with copper or grid-like ground wires. If the copper is not handled properly, it will be very troublesome.
Everyone knows that under high frequency conditions, the distributed capacitance of the wiring on the printed circuit board will work. When the length is greater than 1/20 of the corresponding wavelength of the noise frequency, an antenna effect will occur, and the noise will be emitted through the wiring. If there is a poorly grounded copper pour in the PCB, the copper pour becomes a tool to spread noise. Therefore, in a high-frequency circuit, never think that the ground wire is connected to the ground. It must be less than λ/20, punch through holes in the wiring, and “good ground wiring” with the ground plane of the multilayer board. If the copper coating is handled properly, the copper coating not only increases the current, but also plays a dual role of shielding interference.
In copper coating, in order to achieve the desired effect of copper coating, those issues need to be paid attention to in copper coating:
1. If the PCB has many grounds, such as SGND, AGND, GND, etc., according to the position of the PCB board, the main “ground” is used as a reference to independently pour copper, digital ground and analog ground. It is not necessary to separate the copper pour. At the same time, before the copper pour, first thicken the corresponding power connection: 5.0V, 3.3V, etc., in this way, multiple deformed structures with different shapes are formed.
2. For single-point connection of different grounds, the method is to connect through 0 ohm resistors or magnetic beads or inductance.
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