Ground wire planning
Unreasonable grounding planning can cause interference to printed circuit boards, fail to meet planning targets, and even render them inoperable. The ground wire is the reference point for potential in a circuit and also the common channel for current. In theory, the ground potential is zero potential, but in practice, due to the existence of wire impedance, the potential of the ground wire is not always zero. Because the ground wire only needs to have a certain length and is not an equipotential point with zero everywhere, it is not only an essential common channel for circuits, but also a channel for interference.
One point grounding is the basic principle for eliminating ground wire interference. All grounding wires of circuits and equipment must be connected to a consistent grounding point, which serves as the zero potential reference point (surface) of the circuit or equipment. One point grounding refers to connecting a common ground wire in series with one point grounding and connecting an independent ground wire in parallel with one point grounding.

The method of connecting a common ground wire in series is relatively simple, and the grounding leads of each circuit are relatively short with relatively low resistance. This grounding method is commonly used for grounding in equipment cabinets. An independent ground wire is connected in parallel with a grounding point. As long as a physical point is defined as the grounding reference point, all other points that need to be grounded are directly connected to this point. The ground potential of each circuit is only related to the ground current base impedance of the circuit and is not affected by other circuits.
When detailed wiring, the following points should be noted:
⑴ The wiring length should be as short as possible to minimize the lead inductance. In low-frequency circuits, multi-point grounding is avoided because the ground current of all circuits flows through a common ground impedance or ground plane.
⑵ Public grounding wires should be arranged as much as possible at the edge of the printed circuit board. Copper foil should be stored as much as possible on the circuit board as a ground wire to enhance shielding capability.
⑶ The double-layer board can use a ground plane, and the intention of the ground plane is to provide a low impedance ground wire.
In multi-layer printed circuit boards, grounding layers can be set up and planned in a mesh pattern. The distance between the ground wire grid should not be too large, because one of the primary functions of the ground wire is to provide a signal return path. If the distance between the grids is too large, it will form a large signal loop area. The large loop area can cause radiation and sensitivity issues. In addition, the signal return practice takes the path with a small loop area, and other ground wires do not work.
The ground plane can minimize the radiation loop.
Article source: PCB manufacturerhttp://www.yonghongpcb.com/