PCB wiring is to lay out printed wires according to the PCB circuit schematic diagram, wire table, and required wire width and spacing. So, what knowledge should be mastered in PCB board wiring?
1. On the premise of meeting the requirements, the wiring should be as simple as possible. The order of selecting the wiring method is single-layer-double-layer-multilayer.
2. Grounding wire shielding should be laid next to the input line of the circuit; the wiring of the same layer should be evenly distributed; the conductive area of each layer should be relatively balanced.
3. The direction of the signal line should be changed in an oblique line or a smooth transition to avoid electric field concentration, signal reflection and additional impedance.
4. Digital circuits and circuits should be separated in wiring to avoid mutual interference; signal lines of different frequencies should be separated by grounding wires to avoid crosstalk. For the convenience of testing, necessary breakpoints and test points should be set in the design.
5. When the circuit components are grounded and connected to the power supply, the wiring should be as short as possible and as close as possible to reduce internal resistance.
6. The upper and lower layer traces should be perpendicular to each other to reduce coupling, and the upper and lower layer traces should not be aligned or parallel.
7. Multiple I/O lines of high-speed circuits, and I/O lines of differential amplifiers, balanced amplifiers and other circuits should be equal in length to avoid unnecessary delay or phase shift.
8. When the pcb pad is connected to a large conductive area, a thin wire with a length of not less than 0.5m should be used for thermal isolation, and the width of the thin wire should not be less than 0.13mm.
9. The wire closest to the edge of the SMB should be more than 5mm away from the edge of the SMB, and the ground wire can be close to the edge of the SMB if necessary.
10. The public power lines and grounding lines on the double-sided SMB should be arranged as close to the edge of the SMB as possible, and distributed on both sides of the SMB. The multi-layer SMB can be equipped with a power supply layer and a ground wire layer on the inner layer, and is connected to the power wire and ground wire of each layer through metallized holes.
