1, early preparation
Including the preparation of component libraries and schematics. In the PCB design, we must first prepare the schematic SCH component library and PCB component library.
The PCB component library is preferably built by the engineer according to the standard size information of the selected device. First of all, the establishment of the principle of PC component library, and then establish the schematic SCH component library.
PCB component packaging library requires higher, it directly affects the installation of PCB; schematic SCH component library requirements are relatively loose, but should pay attention to the definition of pin properties and the corresponding relationship between the PCB component library.
2, PCB structure design
Have been identified according to the board size and the mechanical positioning, draw the PCB frame in the PCB design environment, and according to the positioning requirements of connectors, key / switch, placed the screw hole, hole assembly etc..
Fully consider and determine the wiring area and non wiring area (such as the screw hole around the scope of the non wiring area).
3, PCB layout design
The layout design is placed inside the device in PCB frame according to the design requirements. In the schematic tool to generate a network table (Design - Create Netlist), after the introduction of PCB software in the network table (Design - Import). After the successful introduction of the network table will exist in the software background, through the Placement operation can be transferred out of all the devices, there is a connection between the pins of the flight line prompt, then you can layout the device design.
PCB layout design is the first important process in the whole design process of PCB, the more complex the PCB board, the better the quality of the layout can directly affect the degree of difficulty in the realization of the latter.
The layout design depends on the circuit board design and the design experience, which belongs to the higher level. Primary circuit board designer experience is still shallow, suitable for small module layout design or the whole board is difficult to lower PCB layout design tasks.
4, PCB wiring design
PCB wiring design is the most work process in the whole PCB design, which directly affects the performance of the PCB board.
In the design process of PCB, there are three kinds of wiring:
The first is the completion, this is the PCB design of the basic requirements;
The second is to meet the electrical performance, this is a piece of PCB board eligibility criteria, the route is found after carefully adjust the wiring, so that it can achieve optimum electrical performance;
Again is neat and beautiful, even out of order wiring, electrical performance will pass brings great inconvenience in the optimization and testing and maintenance for later modification, wiring requirements are uniform, can not be arranged in a crisscross pattern clueless.
5, wiring optimization and screen printing
"PCB design is not the best, only better", "PCB design is a defect of the art", this is mainly because the PCB design to achieve the design requirements of all aspects of the hardware, and individual requirements may be conflict between.
The general design experience is: optimize the wiring time is two times the initial wiring. PCB routing optimization is completed, the need for postprocessing, the primary treatment is PCB of the surface of the screen logo, design the bottom of the screen characters need to do image processing, in order to avoid confusion with the top screen.
6, network DRC inspection and structural inspection
Quality control is an important part of the PCB design process, the general means of quality control include: self inspection, mutual inspection, expert review meeting, special inspection, etc..
Principle diagram and structure diagram is the most basic elements of design requirements, inspection and check is the DRC network structure were confirmed PCB design to meet the principle of netlist and structural elements of figure two input conditions.
General circuit board designers will have their own accumulation of design quality inspection Checklist, which is part of the entry from the company or departmental norms, the other part of the experience from their own summary. Special inspection, including the design of the Valor inspection and DFM inspection, the two part of the content is concerned with the design of the output of the PCB back-end processing of light drawing documents.
7, PCB board
Prior to the formal processing of the PCB board, the circuit board designer needs to communicate with the PCB PE for the board factory to answer the manufacturer's confirmation of the PCB board processing.
This includes but not limited to: PCB plate models, line layer wire width and distance adjustment, impedance control adjustment, the adjustment of the thickness of PCB layer, surface processing, aperture tolerance control and delivery standards etc..