1. Treatmentof power supply and ground wire

The interference caused by improper treatmentof power supply and ground wire will degrade the performance of products, andsometimes even affect the success rate of products. Therefore, the wiring ofpower supply and ground wire should be taken seriously to minimize the noiseinterference caused by power supply and ground wire.

Specific practices are as follows: (1) Adddecoupling capacitor between power supply and ground. (2) Widen the width ofpower supply and ground wire as much as possible. Usually, the signal linewidth is 0.2 ~ 0.3 mm, the finest width can reach 0.05～0.07mm, and the power line is 1.2 ~ 2.5 mm.(3) For the PCB of digital circuit, a wide ground wire can be used to form aloop. (4) Make it a multilayer board, with one layer for power supply and onelayer for ground wire.

2. Co-locationprocessing of digital circuits and analog circuits. Many PCBs are not singlefunctional circuits, but are composed of digital circuits and analog circuits.

Therefore, it is necessary to consider themutual interference between them when wiring.

The frequency of digital circuit is high, andthe sensitivity of analog circuit is strong.

For the ground wire, PCB has only one node tothe outside world, so it is necessary to deal with the problem of number andcommon ground in PCB.

3. The signal lines are laid on the electrical(ground) layer. When wiring multilayer printed boards, because the signal linelayer is not finished and there is not much space left, adding more layers atthis time will cause waste.

To solve this contradiction, we can considerwiring on the electrical (ground) layer. The power layer should be consideredfirst, and then the stratum.

4. Treatment of connecting legs in large areaconductors In large-area grounding (electricity), pins of common components areconnected with them. As far as the electrical performance is concerned, it isbetter to fully connect the pads of the component pins with the copper surface,but there are some hidden dangers in the welding and assembly of the components:① Welding requires a high-power heater; ② It iseasy to cause virtual solder joints.

5. The role of network system in wiring in manyCAD systems, wiring is determined by the network system. If the grid is toodense, the number of channels will increase, which will inevitably requirehigher storage space of the equipment, and it will also have a great impact onthe computing speed of electronic products. Too sparse grid and too fewchannels have great influence on the routing rate. Therefore, it is necessaryto have a dense and reasonable grid system to support the wiring.