Copper plating is employed to utilize the unused space on the PCB as a reference surface, subsequently filling it with solid copper, which is referred to as copper filling. The primary purpose of copper coating is multifaceted: it aims to reduce ground wire impedance, enhance anti-interference capabilities, diminish voltage drop, and elevate power supply efficiency. Moreover, it aids in reducing loop area when connected to the ground wire. In scenarios where the PCB incorporates multiple grounds such as SGND, AGND, GND, etc., a strategic approach is pivotal for copper pouring. My preferred method involves utilizing the most critical “ground” as a reference to independently pour copper based on the PCB’s processing board layout. By segregating digital ground and analog ground, copper coating can be efficiently executed. Furthermore, prior to copper pouring, it is essential to reinforce corresponding power connections such as V5.0V, V3.6V, V3.3V (for SD card power supply), and so forth. This approach facilitates the formation of multiple deformable structures with distinct shapes.
Challenges in PCB Processing:
Several challenges arise during copper coating. Firstly, addressing single-point connections to different grounds is crucial. Secondly, attention must be paid to copper coating near the crystal oscillator, a high-frequency emission source. An effective method involves copper coating around the crystal oscillator followed by isolating the crystal oscillator shell and grounding it. Thirdly, the issue of isolated islands (dead zones) must be tackled. If deemed significant, defining a ground via and incorporating it is a viable solution.
Choice Between Large-Area Copper Pour and Grid Copper Pour:
The debate between large-area copper pour and grid copper pour lacks a one-size-fits-all answer. Large-area copper-clad designs may lead to board warping and blistering during wave soldering. In contrast, grid designs offer superior heat dissipation. Typically, high-frequency circuits with stringent anti-interference requirements utilize multipurpose grids, whereas low-frequency circuits with substantial currents favor complete copper coverage.
Copper Coating in Digital Circuits:
In digital circuits, particularly those featuring MCUs and operating at frequencies above the megahertz level, copper coating aims to minimize ground plane impedance. A preferred approach involves copper cladding different areas for each core module (including all digital circuits) when feasible, followed by interconnecting the copper-clad areas using wires. This strategy mitigates interference between circuit levels.
Mixed Circuits and Analog Circuit Ground Routing:
In mixed circuits involving both digital and analog components, independent ground wire routing and proper placement of power supply filter capacitors are imperative. Analog circuit ground routing requires meticulous attention due to the interplay between front and rear stages, necessitating single-point grounding. Simulated copper coating in analog circuits demands tailored solutions based on specific requirements and circuit characteristics.
Challenges in PCB Processing:
Several challenges arise during copper coating. Firstly, addressing single-point connections to different grounds is crucial. Secondly, attention must be paid to copper coating near the crystal oscillator, a high-frequency emission source. An effective method involves copper coating around the crystal oscillator followed by isolating the crystal oscillator shell and grounding it. Thirdly, the issue of isolated islands (dead zones) must be tackled. If deemed significant, defining a ground via and incorporating it is a viable solution.
Choice Between Large-Area Copper Pour and Grid Copper Pour:
The debate between large-area copper pour and grid copper pour lacks a one-size-fits-all answer. Large-area copper-clad designs may lead to board warping and blistering during wave soldering. In contrast, grid designs offer superior heat dissipation. Typically, high-frequency circuits with stringent anti-interference requirements utilize multipurpose grids, whereas low-frequency circuits with substantial currents favor complete copper coverage.
Copper Coating in Digital Circuits:
In digital circuits, particularly those featuring MCUs and operating at frequencies above the megahertz level, copper coating aims to minimize ground plane impedance. A preferred approach involves copper cladding different areas for each core module (including all digital circuits) when feasible, followed by interconnecting the copper-clad areas using wires. This strategy mitigates interference between circuit levels.
Mixed Circuits and Analog Circuit Ground Routing:
In mixed circuits involving both digital and analog components, independent ground wire routing and proper placement of power supply filter capacitors are imperative. Analog circuit ground routing requires meticulous attention due to the interplay between front and rear stages, necessitating single-point grounding. Simulated copper coating in analog circuits demands tailored solutions based on specific requirements and circuit characteristics.
