High-quality circuit board principle conversion production process (process)? For hardware circuit designers. Protel99se is a basic skill that must be mastered. If you want to design a high-quality circuit board, you must consider many issues such as the principle of the circuit, the selection of components, and the interference of electromagnetic waves in space. Therefore, the work of designing and drawing a printed circuit board is a complex system project, which requires A lot of pcb design experience and skills.
1) Create a design database file.
2) Create a new circuit schematic diagram.
3) Load the component library, place the components and lay out the schematic wiring.
4) erc and generate netlist. Use the intelligent electrical rule check (erc) function provided by Protel to check the electrical rules of the circuit system, which mainly includes two aspects:
① Check the electrical rules conflict of the schematic diagram, such as connecting the output pin of one component with the output pin of another component;
② Check the network labels that are not connected or reused. The netlist (netlist) is the link between the circuit schematic file and the PCB design.
5) Create a new pcb file and plan the printed circuit board. Planning the circuit board is mainly to determine the physical boundary, electrical boundary, board layer structure and layout requirements of the circuit board.
First, define the shape and size (physical boundary) of the circuit board. The user determines the physical boundary of the circuit board in one of the four mechanical layers, and places the size, corner marks, and reference hole positions on the other mechanical layers. Then, define the electrical boundaries of the circuit board. The electrical boundary is used to limit the range of wiring and component placement. Generally, the user should plan the range of the electrical boundary and the range of the physical boundary to be the same size. All target objects of the signal layer (such as pads, vias, and traces) are confined within the electrical boundary.
6) Set the parameter system. The parameter setting includes the parameters of the working layer, the working parameters of the pcb editor, the setting of automatic layout and wiring number, etc. When designing a printed circuit board, determine its working layers, including signal layers (signal layers), power/ground layers (intemalplanes), (mechanical layers), etc. Printed circuit single-layer board, double-layer board and multi-layer board. In practical applications, the double-layer board has become the most commonly used printed circuit board because of its relatively simple wiring and moderate price. The double-layer board includes two layers of the top layer (toplaye bottom layer), double-sided copper-clad, and an insulating layer in the middle. The double-layer board can be wired on both sides, and generally needs to be connected by vias or pads.
7) Load the network table. The netlist is the key to automatic wiring, and it is the bridge connecting the circuit schematic diagram and the PCB diagram. Only when the netlist is loaded correctly, can the circuit board be automatically laid out and automatically routed.
8) Placement and layout of components. The placement of components must comply with the general rules of component layout. Layout refers to placing the package of components neatly and reasonably within the range defined by the circuit board. There are two ways of layout: manual layout and automatic layout. Manual layout refers to rearranging component packages, pads, vias, strings, etc. manually. For more complex circuits, most of them use automatic layout, and then manually adjust the layout.
9) Routing rules. After the package of the components is laid out on the printed circuit board, it can be routed. Like layout, wiring can be divided into manual wiring and automatic wiring. Complex circuits generally adopt automatic wiring and then manually adjust to achieve the best results. Before the automatic wiring, the first task is to set the “automatic line rules”.
10) Automatic wiring and manual adjustment. Generally speaking, there will be some unreasonable places after PCB automatic wiring, such as excessive wiring turns, repeated wiring connections, and direct wiring through component pins. In addition, in some cases, designers need to place pads, vias, dimensions, and strings to meet actual design needs. For the above situation. Need the designer to adopt the method of manual wiring to complete.
11) The generation of various pcb reports and the output of pcb reports are built for the convenience of users to query and manage the circuit boards. The detailed information of the printed circuit boards can be recorded in various reports. pcb can generate “selected pins report” (selected pins), “board information report” (board information),
“(Bill of materials), “design document report”, “netlist status” (netlist status), “drilling document” and other documents. After wiring the circuit board, you can output the circuit board diagram and send the output result to Produced by the manufacturer.
12) File saving and output After the PCB design is completed, the file should be saved, and then various graphic output devices can be used to output the PCB diagram.
Post time: Aug-05-2021