label: copper PCB,Printed-circuit board,PCB board
Laminate is the so-called unused space on the PCB as a datum, then filled with solid copper, these copper area is also known as copper pour. The significance of copper, reducing the ground impedance, improve anti-jamming capability; reduce the pressure drop, improving power efficiency; connected with the ground, you can also reduce the loop area.
Copper need to pay attention to those aspects of the problem:
1. If the PCB ground more, there SGND, AGND, GND, etc., it is necessary depending on the PCB board positions, respectively, the most important "place" as a baseline reference to independent laminates, digital and analog ground separately copper from the few words, but before the copper, the first bold corresponding power connection: 5.0V, 3.3V, and so on, so that to form a plurality of multi-deformed structures of different shapes.
2. A single point of connection differently, practices are connected via 0 ohm or beads or inductors;
3. Near the copper crystal, crystal oscillator circuit is a high-frequency emission source, practice is surrounded by crystal copper, crystal shell then be grounded.
4. Island (dead zone) problem, if you feel great, then the definition of a ground vias added to it also can not take much to do.
5. At the beginning of wiring, grounding respond equally, when traces on the ground should take a good, can not rely upon the laminates to eliminate by adding vias to connect the ground pin, so that the effect is very bad.
6 on the board is best not to have a sharp angle appears ("= 180 degrees), because from the point of view in terms of electromagnetism, which constitute a transmitting antenna, and for other affected but there will always be a large or small only, I recommend the use of arc along the edge.
7. The middle layer of the multilayer wiring open area, not copper. Because you make this difficult to achieve copper "well grounded."
8. Metal inside the device, such as metal radiators, metal reinforcing strips, etc., must be achieved "well grounded."
9. Three-terminal regulator heat slug must be well grounded. Crystal buffer zone near the ground, must be well grounded. In short: copper PCB, grounding problems if handled well, definitely "more good than harm", it can reduce the reflux area of signal lines, reducing the signal external electromagnetic interference.
Source://www.seekic.com
