After the position and shape of the components on the PCB board are determined, the wiring can be performed according to the position of the components. The following are the basic requirements for the circuit board:
The low frequency wires are placed close to the edge of the printed circuit board. Place low frequency and DC conductors such as power, filtering, and control on the edge of the printed circuit board. The common ground wire should be placed at the edge of the board, and the high-frequency line should be placed in the middle of the board surface to reduce the distributed capacitance of the high-frequency wire to the ground, and also facilitate to connect the ground wire on the pcb board to the rack. The high-potential and the low-potential wire should be kept as far as possible, and it is preferable to minimize the potential difference between adjacent wires during wiring. The distance between the printed conductor and the printed circuit board edge should be no less than the thickness of the board in order to facilitate pcb assembly and improve insulation performance.
Avoid long distance parallel lines. The wiring on the printed circuit board should be short and straight, reduce the parallel wiring, and if necessary, using a jumper. The wires on both sides of the double-sided printed circuit board should cross vertically. The length and width of the printed conductors of the high-frequency circuit should be small, and the conductor spacing should be large.
1.Different signal systems should be separated. When the analog circuit and the digital circuit are both assembled on the printed circuit board, the grounding systems and power supply systems of the two circuits should be completely separated.
2.With the appropriate plug-in form, there are forms of connectors, plug-in ends and wire-outs. The wire of the input circuit should be away from the wires of the output circuit, and the lead wires should be relatively concentrated. When wiring, the input and output circuits are arranged on both sides of the printed circuit board and separated by ground wire.
3.Setting the ground wire. The ground wire of each grade of the circuit on the printed circuit board should generally be self-closed loop to ensure that the ground current of each grade of the circuit mainly flows in the local loop, reducing the current coupling between the 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 an induced current. The higher the operating frequency of the circuit, the wider the ground wire should be, or the large area of copper are applied.
4.Conductors should not have sharp turns and sharp angles. Turning and transition parts should be connected with arcs with a radius of not less than 2 mm or with 450 angles connection line, and branch lines should be avoided.
① Prepare a actual product surface soldered pcb assembly board . Because printed solder paste and the PCB assembly board without soldering cannot fix the test end of the thermocouple, it is necessary to use the soldered actual product for testing. In addition, the test sample cannot be used repea...
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