Basic Design Process and Layout of PCB Design(1)

The basic design process of general PCB design is as follows:

Preliminary preparation-PCB structure design-PCB layout-wiring-wiring optimization and silk screen-network and DRC inspection and structure inspection-plate making.

1.Preliminary preparations include the preparation of component libraries and schematics

“Workers must first sharpen their tools if they want to do their jobs well.” In order to make a good board, in addition to designing the principles, you must also draw well. Before proceeding with PCB design, you must first prepare the schematic SCH component library and PCB component library. The component library can use Peotel’s own library, but it is generally difficult to find a suitable one. It is best to make your own component library based on the standard size data of the selected device. In principle, do the PCB component library first, and then do the SCH component library.

PCB component library requirements are high, which directly affects the installation of the board. SCH component library requirements are relatively loose, just pay attention to the definition of the pin attributes and the corresponding relationship with the PCB components. Pay attention to the hidden pins in the standard library. After that is the design of the schematic diagram, and when it is done, it is ready to start the PCB design.

2. PCB Structure Design

In this step, draw the PCB surface in the PCB design environment according to the determined circuit board size and various mechanical positioning, and place the required connectors, buttons/switches, 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 area around the screw hole belongs to the non-wiring area).

3. PCB Layout

The layout is to put devices on the board. If all the preparations mentioned above are done, you can generate the netlist on the schematic, and then import the netlist on the PCB diagram. You can see the whole stack of devices crashing, and there are flying wires between the pins to indicate the connection. Then you can lay out the device. The general layout is carried out according to the following principles:

(1) Reasonably partition according to electrical performance. It is generally divided into: digital circuit area (that is, fear of interference and interference), analog circuit area (fear of interference), power drive area (interference source).

(2) Circuits that complete the same function should be placed as close as possible, and the components should be adjusted to ensure the most concise connection. And adjust the relative position between the functional blocks to make the connection between the functional blocks the most concise.

(3) For high-quality components, the installation location and installation strength should be considered. Heating components should be placed separately from temperature-sensitive components. And heat convection measures should be considered when necessary.

(4) The I/O driver should be as close as possible to the edge of the printed board and to the lead-out connector.

(5) The clock generator (such as crystal oscillator or clock oscillator) should be as close as possible to the device that uses the clock.