It can be said that pcb wiring is the most important and time-consuming process in the entire PCB design. Here we share some pcb wiring principles.
1. Layered wiring: separate the power and load parts of the power supply to avoid mutual interference and improve the signal-to-noise ratio.
2. Appropriately increase ground copper: Ground copper can effectively reduce electromagnetic interference, so in the power supply part, ground copper can be appropriately increased.
3. Select the appropriate line width: according to the size of the current and the length of the distance, select the appropriate line width to ensure the safety and stability of the circuit.
4. Pay attention to the wiring near the power regulator chip: filter capacitors and noise reduction capacitors need to be arranged near the voltage regulator chip to ensure the stability of the power supply.
5. Separate wiring: Separate the input and output power lines to prevent the output signal from interfering with the input signal.
6. Eliminate loops: When laying out power lines, it is necessary to ensure that no loops are formed to prevent noise.
7. The closer the wiring distance, the better: Keep the power wiring distance as small as possible to help reduce the interference of power fluctuations on the circuit.
8. Symmetrical wiring: When arranging power lines, it should be as symmetrical as possible to avoid interference and circuit stability problems.
9. Keep the length of the power line as short as possible: Keeping the power line as short as possible will reduce the level of noise and modulation interference, thereby improving the stability and performance of the circuit.
10. The connection of the ground wire is strong enough: the ground wire of the power supply part needs to be connected firmly and reliably to ensure the normal operation of the ground.
11. The capacitance of the bypass ceramic capacitor should not be too large, and its parasitic series inductance should be as small as possible. Multiple capacitors connected in parallel can improve the impedance characteristics of the capacitor;
12. The parasitic parallel capacitance of the inductor should be as small as possible, and the farther the distance between the inductor pin pads, the better;
13. Avoid placing any power or signal traces on the ground plane;
14. The area of the high-frequency loop should be reduced as much as possible;
15. The placement of via holes should not destroy the path of high-frequency current on the formation;
16. A small circuit on the system board needs different ground layers, and the ground layer of the small circuit is connected to the power ground layer through a single point;
17. The drive circuit loop from the control chip to the upper and lower FETs should be as short as possible;
18. Switching power supply power circuit and control signal circuit components need to be connected to the ground plane of Xiaotong, and these two ground planes are generally connected through a single point.
19. In PCB layout, it is inevitable to turn the traces. When the traces have right-angled corners, additional parasitic capacitance and parasitic inductance will be generated at the corners. Acute angles and right angles should be avoided in PCB design, resulting in unnecessary radiation, and the performance of PCB production process is not good.
20. The routing directions of adjacent planes form an orthogonal structure. Avoid running different signal lines in the same direction on adjacent layers to reduce unnecessary crosstalk between layers.