PCB Tech - EMC design steps of PCB circuit board

The PCB circuit board can combine a lot of electronic components, which can save space and will not hinder the operation of the circuit. When the PCB circuit board is designed, there are many processes. First, we have to set Good PCB circuit board parameters. Secondly, we have to install each part in the right place.

1. Enter the PCB design system and set relevant parameters

Set the environmental parameters of the design system according to personal habits, such as the size and type of grid points, the size and type of cursor, etc. Generally speaking, the system default values can be used. In addition, parameters such as the size and number of layers of the circuit board must be set.

2. Generate and import the network table

The netlist is the bridge and tie between the circuit schematic design and the printed circuit board design, and it is very important. The netlist can be generated from the schematic diagram of the circuit, or extracted from an existing money-system circuit board file. When the netlist is introduced, errors in the circuit schematic design need to be checked and corrected.

3. Arrange the location of each part package

The automatic layout function of the system can be used, but the automatic layout function is not perfect, and it is necessary to manually adjust the position of each part package.

4. Carry out circuit board wiring

The prerequisite for the automatic wiring of the circuit board is to set the safety distance, wire form and so on. At present, the automatic wiring function of the equipment is relatively complete, and general circuit diagrams can be routed; but the layout of some lines is not satisfactory, and wiring can also be done manually.

5. Save through printer output or hard copy

After completing the wiring of the circuit board, save the completed circuit circuit diagram file, and then use various graphic output devices, such as a printer or a plotter to output the circuit board wiring diagram.

Electromagnetic compatibility refers to the ability of electronic equipment to work in a coordinated and effective manner in various electromagnetic environments. The purpose is to enable electronic equipment to suppress all kinds of external interference, so that the electronic equipment can work normally in a specific electromagnetic environment, and at the same time to reduce the electromagnetic interference of the electronic equipment itself to other electronic equipment. As a provider of electrical connections for electronic components, what is the compatibility design of PCB circuit boards?

1. Choose a reasonable wire width. Since the impact interference caused by the transient current on the printed lines of the PCB circuit board is mainly caused by the inductance of the printed wires, the inductance of the printed wires should be minimized.

2. According to the complexity of the circuit, a reasonable choice of the number of layers of the PCB can effectively reduce electromagnetic interference, greatly reduce the size of the PCB and the length of the current loop and branch wiring, and greatly reduce the cross-interference between signals.

3. Using the correct wiring strategy and equal wiring can reduce the wire inductance, but the mutual inductance and distributed capacitance between the wires increase. If the layout permits, it is best to use a grid-shaped wiring structure with a cross-cut pattern. The specific method is that one side of the printed board is horizontal. Wiring, the other side of the vertical wiring, and then use metallized holes at the cross hole to connect.

4. In order to suppress the crosstalk between the wires of the PCB circuit board, try to avoid long-distance equal routing when designing the wiring, and extend the distance between the wires as much as possible, and the signal wire and the ground wire and the power wire should not cross. Setting a grounded printed line between some signal lines that are very sensitive to interference can effectively suppress crosstalk.