Copy board and reliable grounding technology

  PCB copy board and reliable grounding technology is applied to the multi-layer PCB, also applied to the single PCB. Grounding technique for the objective is to minimize the grounding impedance, thereby reducing from the circuit to return to power among the ground loop electric potential.
   ( 1) monolayer PCB grounding wire
   In the single ( single) PCB, grounding wire width should be wide, and must be at least 1.5mm ( 60 mil ). Because of the single layer PCB can not be achieved star wiring, so the jumper and line width changes should be kept as minimum, otherwise it will cause the line impedance and the inductance.
   ( 2) double PCB grounding wire
    In the double ( double ) PCB, for digital circuits use priority grille / lattice wiring, wiring methods can reduce the grounding impedance, grounding circuit and signal loop. As in the single layer PCB, ground and power line width should be at least 1.5 mm.
   Another layout is the ground aside, signal and power line on the other side. In this arrangement will further reduce the grounding circuit and impedance, the decoupling capacitor can be placed at a distance of IC power supply line and the ground plane as much as possible between close.
   ( 3) the protection ring
   Protection ring is a can full of noise environment ( such as radiofrequency current ) isolation ring in the outer earth technology, this is because in the usual operation of no current flows through the protection ring.
   ( 4) the PCB capacitor
   In multilayer, by separating the power plane and ground insulation thin layer produces a PCB capacitor. In the single board, power line and ground line of the parallel arrangement will also cause the capacitance effect. PCB capacitor is an advantage in that it has very high frequency response and uniformly distributed on the surface or the entire line of low series inductance.
   It is equivalent to a uniform distribution over the entire board of the decoupling capacitor. No single discrete components have the characteristics of.
   ( 5) circuit in high speed and low speed circuit
   High speed circuit shall be arranged so that it is more close to the ground, and low speed circuit should be close to the power plane.
   ( 6) the copper filled
   In some analog circuit, without the use of regions of the circuit board is composed of a large ground to cover, thereby providing shielding and decoupling ability. But if the copper area is vacant ( for example it is not and connected ), then it may manifest as an antenna, and will lead to the problem of electromagnetic compatibility.
   ( 7) in a multilayer PCB ground and power planes
   In a multilayer PCB, recommend the power plane and ground as close as possible is placed in the adjacent layer, so as to allow the whole board produces a large PCB capacitor. The fastest key signals should be near the ground side, a key signal is placed near the power plane.
   ( 8) power requirements
     When the circuit needs to be more than just a power supply, the ground will each power. But in a single PCB multiple grounding is not possible. A solution is to take from a power supply from the power line and ground with the other power line and ground wire spaced apart. It also helps to avoid the noise coupling between the power source.
    This article describes the various methods and techniques is beneficial to improving the PCB EMC properties, of course these just EMC design part, usually consider the reflection noise radiation emission, noise, and other technical problems caused by interference. In the actual design, according to the design requirement and design conditions, adopting reasonable anti interference measures, design a good EMC performance PCB circuit board.