What is Copper Clad

The so-called Copper Clad is to use the unused space on the flexible circuit board as a reference surface and then fill it with solid copper. These copper areas are also called copper filling. The significance of Copper Clad 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 to the ground wire can also reduce the loop area. Also for the purpose of making the PCB as non-deformed as possible during soldering, most PCB manufacturers will also require PCB designers to fill the open areas of the PCB with copper or grid-like ground wires. If the Copper Clad handles improperly, it will Whether the gains or losses are rewarded or lost, is Copper Clad “pros greater than disadvantages” or “harms greater than benefits”?

Everyone knows that under high frequency, the distributed capacitance of the wiring on the printed circuit board will play a role. 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 Clad in the PCB, the Copper Clad becomes a tool for spreading noise. Therefore, in a high-frequency circuit, do not think that a ground wire is connected to the ground. This is the “ground”. “Line”, must be less than λ/20, punch through holes in the wiring, and “good ground” with the ground plane of the multilayer board. If the Copper Clad is handled properly, Copper Clad not only increases the current, but also plays a dual role of shielding interference.

Copper Clad generally has two basic methods, namely large-area Copper Clad and grid copper. It is often asked whether a large-area Copper Clad is better or a grid Copper Clad. It is not good to generalize. why? The large-area Copper Clad has the dual functions of increasing current and shielding. However, if the large-area Machining Copper Clad is subjected to wave soldering, the board may lift up or even bubble. Therefore, a large-area Copper Clad usually has several grooves to relieve the blistering of the copper foil. The simple mesh Copper Clad is mainly a shielding function, and the effect of increasing the current is reduced. From the perspective of heat dissipation, the mesh is beneficial. (It lowers the heating surface of the copper) and plays a role of electromagnetic shielding to a certain extent.

It should be pointed out that the grid is made up of traces in staggered directions. We know that for the circuit, the width of the trace has a corresponding “electrical length” for the operating frequency of the circuit board (the actual size is divided by The digital frequency corresponding to the working frequency is available, see related books for details), when the working frequency is not very high, perhaps the role of the grid line is not very obvious, once the electrical length matches the working frequency, it will be very bad, you will It is found that the circuit is not working properly at all, and signals that interfere with the operation of the system are being transmitted everywhere. So for colleagues who use grids, my suggestion is to choose according to the working conditions of the designed circuit board, and don’t cling to one thing. Therefore, high-frequency circuits have high requirements for multi-purpose grids for anti-interference, and low-frequency circuits have circuits with large currents, such as commonly used complete copper stamping blanks.