Before we design the PCB board, we must understand the wiring process of the PCB board. Let me explain it to you in detail:
1. Draw the correct schematic diagram and netlist The schematic diagram is the premise of designing the PCB board, and the netlist is the bridge connecting the schematic diagram and the PCB board diagram.
2. Determine the component package and complete the conversion from schematic diagram to PCB. Protel99SE provides a rich standard component library. Before importing the netlist file, you must first load the PCB component package library to ensure that all used libraries have been loaded.
3. Set the environment parameters. Set environmental parameters according to your own habits, such as grid size, cursor capture size, conversion of metric and imperial units, etc. In addition, the layer of the PCB board must be set.
4. Design the circuit board. It is mainly to set various physical parameters of the circuit board, including whether the circuit board is a double-layer board or a multi-layer board, the shape and size of the circuit board, and the installation method of the circuit board.
5. Import the network table. The netlist includes the packaging form of each component and the connection relationship between the components. Importing the netlist will obtain the basis for the subsequent design of the PCB.
6. Layout of components. First arrange the devices related to the mechanical size and lock these devices, then arrange the larger and more space-consuming devices and the core components of the circuit, and finally arrange the peripheral small components.
7. Formulate detailed wiring rules. Routing rules include trace spacing, various line widths, size of vias, topology of wiring, etc., which need to be set according to the actual situation of the design. Also, place fill in areas where traces are not expected.
8. PCB wiring. This step includes three steps: manual wiring, automatic wiring and manual adjustment.
9. The processing of the terminal of the circuit board. In the design, the power supply, grounding, signal input and output terminals must be connected to the outside world, and the lead-out method depends on the process requirements. The common lead-out methods are lead-out by pad and lead-out by connector.
10. Copper application and teardrop filling. In order to enhance the anti-interference ability of the circuit board, it is necessary to apply copper to the ground wire network of each wiring layer. In addition, teardrop filling is required for all vias and pads.
11. Perform a design rule check. In order to ensure that the circuit board diagram conforms to the design rules and that all nets are connected correctly, a design rule check must be done after wiring.
12. Adjust the information on the rest of the layers. After passing the design rule check, drag and drop all the characters of the silk screen layer to the appropriate position, and finally put the name of the printing plate, design version number, company name, date of first processing of the file and other information.
13. Save and export printed board files. After the design is completed, it is necessary to sort out, archive and print the drawings of the printed board files. In addition, parts lists can be exported, spreadsheet documents can be generated as parts lists, etc.
