PCB Design Process and Considerations

PCB (Printed Circuit Board) design process generally includes the following steps:

Pre-preparation: Including the preparation of component libraries and schematics. Before PCB design, the first thing to do is to prepare the schematic SCH component library and PCB component library. Component library can use peotel comes with the library, but in general it is difficult to find the right one, it is best to do their own component library according to the standard size of the selected device information. In principle, the first PCB component library, and then do the SCH component library.

PCB Structural Design:  According to the size of the board has been determined and the mechanical positioning, in the PCB design environment to draw the PCB board, and according to the positioning requirements placed on the required connectors, buttons / switches, screw holes, assembly holes and so on. And fully consider and determine the wiring area and non-wiring area (such as screw holes around how much belongs to the non-wiring area).

PCB Layout: Layout is to put the device on the board. Then you can layout the device.

Wiring:Wiring is the process of connecting the designed circuits. This step requires engineers to fully consider various factors, such as the flow of signals, electromagnetic interference, the topology of the wiring and so on, in order to ensure the stability and reliability of the circuit.

Wiring Optimization and Silkscreen: After the wiring is completed, a series of optimization work needs to be carried out, such as adjusting the length of the alignment and optimizing the signal quality. At the same time, screen printing operation is also required, i.e., printing the necessary text and patterns on the circuit board to facilitate production and maintenance.

Network and DRC Check and Structural Check: After completing the wiring and silk-screening, a network and DRC check and a structural check are required to ensure that the electrical characteristics and mechanical structure of the board meet the requirements.

Plate Making: The final step is plate making, which is the process of making the actual circuit board from the designed board. This step requires the use of professional plate-making equipment, in accordance with the design of the drawings on the copper plate processing, the final formation of the circuit board.

PCB Material Selection: According to the circuit needs and performance requirements, select the appropriate PCB material, such as FR4, CEM-1, aluminum substrate.

PCB Layer Design: According to the circuit complexity and signal requirements, design the appropriate number of PCB layers, multi-layer board can provide more wiring space and better signal integrity.

Impedance Control: For signal lines with special impedance requirements, impedance control design is needed to ensure the stability and reliability of signal transmission.

Heat Dissipation Design: For circuit boards with a large number of heat-generating components, heat dissipation design is required, such as increasing heat sinks and optimizing component layout.

Electromagnetic Compatibility Design: Consider electromagnetic compatibility, shielding and grounding of key signal lines to reduce electromagnetic interference and signal coupling.

Maintainability Design: Consider maintainability in circuit board design, such as reserving test points and maintenance interfaces.

Reliability Testing: Reliability testing, such as temperature cycling test, vibration test, etc., before the production of circuit boards to ensure the reliability and stability of the circuit board.

Overall, the PCB design process is a systematic project that requires comprehensive consideration of multiple aspects, including circuit requirements, material selection, layer design, impedance control, heat dissipation design, electromagnetic compatibility design, maintainability design and reliability testing. Through reasonable processes and details, it can ensure that the final design of the circuit board meets the requirements and has good performance and reliability.

In the PCB design process, the following matters need to be noted:

Component layout, pay attention to the direction of the arrangement of components and the distance between each other, especially the matching and arrangement of large, medium and small components, to try to maintain uniformity and coordination.

The layout of power lines, ground lines and other wires should be reasonable to minimize the mutual interference between them.

In the multilayer board design, pay attention to the direction and distribution of the signal lines between the layers to minimize the cross and interference between them.

In the wiring process, pay attention to the direction and width of the line to avoid the phenomenon of "backflow".

In the wiring, need to pay attention to the length and spacing of the signal line, to avoid signal interference and transmission delay caused by the length is too long or spacing is too small.

In the design process, the size, shape and weight of the circuit board should be fully considered to facilitate subsequent processing and assembly.

Consider the convenience of testing and maintenance in the design, leaving enough test points and interfaces.

Consider the electromagnetic compatibility (EMC) in the design, and take appropriate measures to reduce electromagnetic interference (EMI) problems.

Consider the heat dissipation of the components in the design, and reasonably plan the heat dissipation path and heat sink installation location.

Consider the production cost in the design, select the appropriate materials, processes and assembly methods.