First: preparation
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1. This includes preparing component libraries and schematics. \"If you want to do a good job, you must first sharpen your tools.\" To make a good board, in addition to designing good principles, you must draw well. Before proceeding to PCB design, first prepare the component library of schematic SCH and the component library of PCB (this is the first step - important). The component library can be used with Protel's own library, but in general it is difficult to find the right one, it is best to make your own component library according to the standard size data of the selected device.
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In principle, first do the PCB component library, and then do the SCH component library. PCB component library requirements are high, it directly affects the installation of the board; SCH's component library requirements are relatively loose, as long as attention is paid to defining pin attributes and the corresponding relationship with PCB components.
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PS: Note the hidden pins in the standard library. After that, the schematic design is ready to start PCB design.
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2, when making the library of the schematic diagram, pay attention to whether the pin is connected\/output PCB board to check the library made.
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Second: PCB structure design
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This step is based on the determined board plane size and mechanical positioning, drawing the PCB board surface in the PCB design environment, and placing the required connectors, keys\/switches, digital tubes, indicators, input, output, screw holes, assembly holes, etc., according to the positioning requirements. And fully consider and determine the wiring area and non-wiring area (such as how much of the area around the screw hole belongs to the non-wiring area).
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(Special attention should be paid to the actual size of the components (occupied area and height), the relative position between the components - space size, and the surface of the device placement to ensure the electrical performance of the circuit board and the feasibility and convenience of production and installation. At the same time, it should be ensured that the above principles can be reflected under the premise of Appropriately modify the placement of the device, so that it is neat and beautiful, such as the same device should be placed neatly, in the same direction, and can not be placed \"scattered\").
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Third: PCB layout
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1, make sure the schematic is correct before layout - this is very important! ----- is very important!
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Schematic drawing completed check items: power network, ground network, etc.
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2, layout should pay attention to the surface of the device placement (especially plug-ins, etc.) and the placement of the device (straight insert is lying down or vertical) to ensure the feasibility and convenience of installation.
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3, the layout is to put devices on the board. At this time, if the above-mentioned preparations are done, you can generate a network table on the schematic diagram (Design-> CreateNetlist), and then import the network table on the PCB (Design-> LoadNets). You can see that the devices are all piled up, and there are flying lines between the pins, and then you can layout the devices.
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The general layout is carried out according to the following principles:
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The layout should determine the face of the device placement: Generally speaking, the patch should be placed on the same side, and the plug-in should depend on the specific situation.
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According to the reasonable partition of electrical performance, it is generally divided into: digital circuit area (that is, afraid of interference, and interference), analog electricity
The basic process of general PCB circuit board design is as follows:
Preliminary preparation -> PCB Structure design -> PCB Layout -> Wiring -> Wiring optimization and screen printing -> Network and DRC inspection and structural inspection -> Making plates.
Finally, check the Keepout layer, top layer, bottom layer topoverlay, bottomoverlay.
The above information is from the Internet query, only for the reference of the questioner