Laminate is the unused space on the PCB as a datum , then filled with solid copper , the 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 ; well connected with the ground , reducing the loop area . If the PCB ground more, there SGND, AGND, GND, and so on , how the copper ? My approach is , depending on the PCB board positions , respectively, the most important " place " as a baseline reference to separate the copper , digital and analog ground to separate the copper from the few words . Meanwhile before the copper , the first bold corresponding power connection : V5.0V, V3.6V, V3.3V (SD card supply ) , and so on. Thus , the formation of a plurality of different shapes of a deformation structure .
Laminate need to address several issues : First, a single point of connection differently , the second is near the copper crystal , crystal oscillator circuit is a high-frequency emission source , practice is surrounded by crystal copper , and then the crystal shell separately grounded. Third is an 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.
In addition , a large area of copper-clad laminates good or mesh well , not to generalize. Why? Large copper , if the wave soldering , it could tilt the board , and even blistering. From this point, the grid is better heat dissipation . Usually a high-frequency circuits for interference demanding multi- grid, low-frequency high-current circuit has a circuit full of other commonly used copper shop .
Supplementary follows:
In digital circuits , especially with the MCU circuit , the role trillion level above the operating frequency of the circuit , copper is to reduce the overall impedance ground plane . More specific approach I generally like to operate : Each core module ( also all digital circuits ) in the district will be permitted copper , and then use copper wire to connect the individual , but also the purpose of doing so to reduce the influence of the circuit between the levels .
For digital circuits analog circuits hybrid circuits , independent ground traces , and finally to the summary at the power supply filter capacitor is not to say , we all know . But one thing : the distribution of analog circuits in the ground , often not simply a piece of copper deposited on the matter , because it is focused on analog circuits in each level before and after the impact , but also requires a single -point analog ground to ground , so can not put analog to apply to copper have processed according to the actual situation. ( This requires the use of some special performance analog IC still want to know ).
