As one of the most difficult parts in PCB design, PCB wiring sometimes may make experienced engineers stuck in confusion. Thus, it’s quite essential for us to learn some PCB wiring techniques and skills.
The power supply and ground wire
1. Adding a decoupling capacitor between the power supply and ground wire is
necessary. You should make sure that the power has been through the decoupling capacitor, and then connected to the chip pin. Decoupling capacitors generally serve two functions. Firstly, it provides the chip with instantaneous high current. Additionally, the power supply noise can be removed as decoupling capacitors reduce the noise influence on chips as much as possible, and the chip noise won’t affect the power supply simultaneously.
2. The power supply and ground wire should be widened as much as possible. It is better to set the ground wire wider than power supply, and signal line comes last.
3. You can use a large area of copper for the ground line and make the vacancy in PCB board be connected with the ground.
The mix of digital circuit and analog circuit
Nowadays, PCB is composed by the mix of digital circuit and analog circuit instead of the circuit of single function. Thus, we need to avoid the interference of them in PCB wiring, especially the noise interference on the ground wire. Actually, digital circuit is of high frequency while analog circuit sensitivity is strong. But, the high-frequency signal circuits should be as far as possible away from the sensitive analog ones. That is why the separation of digital circuit and analog circuit is an important principle.
The treatment of trace corner
Generally speaking, the traces corner will bring the thickness changes. If the corners are different, then the changes and influences of line thickness will be different, too.
Hence, the choice of corner angle should be based on the signal sensitivity. Though fillet performs well but is hard to deal with in PCB design, then it is only used for those very sensitive lines. For the signals of average sensitivity, 45-degree angle will be suitable.
In short, the techniques and methods mentioned above are summed up from countless experiences, so it is very worthy to learn and then put into practice. If applied properly, those tips can help you quickly and effectively complete the PCB wiring. More importantly, regardless of PCB wiring and overall layout, you should be as careful as possible. After all, we do not want to see the final products become a waste merely caused by a very small mistake.