PCB design process

PCBDesign Process Reprinted from: http://www.pcbhz.com/html/Services/pcbsj/pcblc/ First, make preparations. This includes preparing the component library and schematic. In progress PCB Before design, prepare the schematic diagram. SCH Component Library and PCB Component Library. Component Library can be used Peotel It is difficult to find a suitable library, but it is best to build a library based on the standard size of the selected device. First in principle PCB Component Library, and then SCH Component Library. PCB The Component Library has high requirements, which directly affects the installation of the Board; SCH Component Library requirements are relatively loose, as long as you pay attention to the definition of Pin attributes and PCB The corresponding relationship of the component is enough. second: PCB structure design. This step is based on the determined circuit board size and various mechanical positioning, in PCB draw in design environment PCB panel, and place the required connectors and buttons as needed / switch, screw hole, assembly hole, etc. And fully consider and determine the wiring area and non-wiring area (such as the scope around the screw hole is not wiring area ). Third: PCB Layout. In other words, the layout is to place the device on the board. At this time, if the preparations mentioned above are all done well, you can generate a network table on the schematic diagram ( Design-> Create
Netlist ), And then PCB Import the network table on the graph ( Design-> Load
Nets ). We can see that all the devices are stacked up, and there is a flying line between each pin to prompt the connection. Then you can layout the device. -- Yes Pay special attention to the fact that when placing components, you must consider the actual size (occupied area and height) of the components and the relative position between the components, to ensure the electrical performance of the circuit board and the feasibility and convenience of production and installation Benefits at the same time, we should modify the placement of devices properly to make them neat and beautiful while ensuring the embodiment of the above principles. For example, the placement of the same devices should be neat and the direction should be consistent, it cannot be set to "Incorrect" . This step is related to the overall image of the board and the difficulty of wiring the next step, so it takes a lot of effort to consider it. During layout, you can make a preliminary wiring for some areas that are not certain, and make full consideration. 4. wiring. Wiring is the whole PCB The most important process in design. This will directly affect PCB The performance of the Board is good or bad. In PCB In the design process, there are generally three levels of wiring: first, wiring, then PCB Set The most basic requirements of timing. If the line is not deployed and the result is a flying line, it will be an unqualified board. It can be said that there is no entry level. The second is the performance of electrical appliances. This is a measure of whether a printed circuit board is integrated. Standard. After the wiring is completed, adjust the wiring carefully so that it can achieve the best electrical performance. Then there is beautiful. If your wiring passes, there is no impact on the electrical performance, but you can see it at a glance. Chaotic, and colorful, colorful, green, then even if your electrical performance is good, in the eyes of others is still a piece of garbage. This will cause great inconvenience to testing and maintenance. Uniform wiring, not vertical and horizontal There is no rule for errors. These must be achieved when the electrical appliance performance is guaranteed and other individual requirements are met.

Fifth, wiring optimization and silk screen printing. "No best, only better "! No matter how hard you design it, after you finish the painting, you will still feel that many places can be modified. The general design experience is that the cabling optimization time is twice the initial cabling time. I feel that there is no need to modify it, so I can lay copper ( Place-> Polygon
Plane ). Copper is usually laid on the ground line (note the separation of analog ground and digital ground), and power may also need to be laid on the multi-layer board. For silk screen printing, be sure not to be blocked by the device or be removed by the through hole and pad. At the same time, the design should face up to the component surface, and the underlying words should be mirrored to avoid confusion. Sixth: Network and DRC Check and structure check. First, the generated PCB Check the network connection relationship between the network file and the schematic network file ( Netcheck ), And promptly correct the design based on the output file results to ensure the correctness of the wiring connection relationship. PCB Design DRC Check and correct the design according to the output file results to ensure PCB Electrical Performance of cabling. Finally, we need PCB To check and confirm the mechanical installation structure. 7. Plate Making. Before that, it is best to have a review process.PCBDesign is a matter of mind-tested work. It is good for you to think carefully and have high experience. Therefore, we should be extremely careful in design, and fully consider the factors in various aspects (for example, for the convenience of maintenance and inspection, many people will not consider it). To keep improving, we will be able to design a good board. PCBThe design flowchart is as follows: