The ten characteristics of PCB power supply design and wiring are as follows:
1) Decoupling should be carried out between the power pin and the ground pin of the chip. The decoupling capacitor should be mounted close to the chip to minimize the loop area of the decoupling capacitor.
2) Try to widen the width of the power line and ground line, preferably the ground line is wider than the power line. The power line should be more than 1mm long.
3) Multiple power signals are routed on the surface of the two-layer board, and multiple ground signals are routed on the other layer, so that the power and ground signals are arranged in a "well" shape, and basically no loops are used.
4) The PCB of the digital circuit can be used to form a loop with a wide ground wire, that is, to form a ground network, and the ground of the analo circuit cannot be used in this way.
5) Use a large area of copper layer as the ground wire, and connect the unused places to the ground as the ground wire on the printed board, or make a multi-layer board, and the power supply and the ground wire each occupy one layer.
6) Generally, it is grounded nearby, but it is necessary to distinguish between analo and digital grounds: analo devices are connected to analo grounds, digital devices are connected to digital grounds; large-signal grounds and small-signal grounds are also separated.
7) For circuit boards with both analo and digital functions, the analo ground and digital ground are usually separated and only connected at the power supply to avoid mutual interference. Do not overlap the digital power supply with the analo power supply, otherwise coupling capacitance will be generated and the separation will be destroyed.
8) The comb-shaped ground wire should be avoided. This structure makes the signal return loop very large, which will increase radiation and sensitivity, and the common impedance between chips may also cause circuit misoperation.
9) When choosing a SMD chip, try to choose a chip with the power pin and the ground pin close to each other, which can further reduce the power supply circuit area of the decoupling capacitor, which is conducive to the realization of electromagnetic compatibility. When multiple chips are installed on the board, there will be a large potential difference on the ground, so the ground should be designed as a closed loop to improve the noise tolerance of the circuit.
10) For circuit parts with the same structure, use "symmetrical" layout as much as possible
