After the position and shape of components on the PCB board are determined, wiring can be carried out according to the position of components.
The following are the basic requirements of the circuit board: ① low-frequency wires are arranged near the edge of the printed circuit board.
Place low frequency and DC wires such as power supply, filtering and control on the edge of the printed circuit board.
The public ground wire should be arranged at the most edge of the board, and the high-frequency wire should be placed in the middle of the board to reduce the distributed capacitance of the high-frequency wire to the ground, and also facilitate the connection between the ground wire on the PCB board and the rack.
High potential wires and low potential wires should be as far away as possible, and it is better to minimize the potential difference between adjacent wires when wiring.
During wiring, the distance between the printed wire and the edge of the printed circuit board shall be not less than the thickness of the board, so as to facilitate pcb assembly and improve insulation performance. 2, avoid long-distance parallel routing.
The wiring on the printed circuit board should be short and straight, reduce parallel wiring, and jumper wiring can be used when necessary.
The wires on both sides of the double-sided printed circuit board shall cross vertically.
The length and width of printed wires of high-frequency circuits should be small and the wire spacing should be large. ③, Different signal systems should be separated.
When the analog circuit and the digital circuit are assembled on the printed circuit board at the same time, the ground wire system of the two circuits should be completely separated, and their power supply systems should also be completely separated.
(4), adopt appropriate plug-in forms, including connectors, plug-in terminals and wire lead-out forms.
The wires of the input circuit should be far away from the wires of the output circuit, and the outgoing lines should be set relatively centrally.
During wiring, the input and output circuits are separated on both sides of the printed circuit board and separated by ground wires. 5 set the ground wire.
The ground wire of each stage circuit on the printed circuit board shall generally form a closed circuit to ensure that the ground current of each stage circuit mainly flows in the local circuit and reduce the coupling of ground current between stages.
However, when there is a strong magnetic field near the printed circuit board, the ground wire cannot be made into a closed loop, so as not to become a closed coil and cause induced current.
The higher the operating frequency of the circuit, the wider the ground wire, or a large area of copper.
⑥ The conductor should not have sharp bends and sharp corners. The turning and transition parts should be connected by an arc with a radius of not less than 2mm or a 450 angle, and branch lines should be avoided.
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