April 20, 2021
PCB design is a very important link in the design of electronic products, and it is an important carrier of electronic products. A good PCB not only has a good appearance, but also needs to meet the requirements of high cost performance, good electrical performance, high stability and reliability, easy production and maintenance, and easy certification. Some technical tycoons believe that as an excellent PCB engineer, one should have the following knowledge structure:
1. Familiar with at least one industry mainstream EDA tool
There are many PCB design softwares, currently the main ones used in the market include the following four: CadenceAllegro, Mentor
EE, MentorPads, AlTIumDesigner, Protel, etc., among which CadenceAllegro has the highest market share.
Allegro has many advantages, such as friendly software interface, fast response speed, high operating efficiency, rich secondary development functions, perfect rule manager functions, powerful high-speed design exclusive functions, and so on. It supports large-scale projects well, and will not greatly reduce the response speed due to the increase in design scale. There is basically no pressure to do tens of thousands of Pin design projects with Allegro. Therefore, for the communications industry, commercial servers, and industrial control, It is very applicable to the military industry.
2. Familiar with devices, read circuit schematics, and recognize key signals
Commonly used electronic components: resistors, capacitors, inductors, transformers, diodes, transistors, field effect tubes, optocouplers (OC), sensors, crystal oscillators, relays, buzzers, rectifier bridge stacks, filters, switches, fuses, etc. .
Key signals include: power, analog signals, high-speed signals, clock signals, differential signals, synchronization signals, etc.
3. Familiar with the manufacturing process and technology of several commonly used board and circuit board factories
Commonly used boards: cardboard, semi-glass fiber board, FR-4 fiberglass board, aluminum substrate, etc.
4. Familiar with the assembly process and technology of patch plug-in
Mainly understand surface mount technology (SMT), through hole insertion technology (THT), etc.
5. Familiar with welding test
Solderability testing is generally used to make a qualitative and quantitative assessment of the solderability of components, printed circuit boards, solders and fluxes. In the assembly and welding process of electronic products, the quality of welding directly affects the quality of the whole machine. Therefore, in order to improve the welding quality, in addition to strictly controlling the process parameters, it is also necessary to conduct scientific solderability tests on the printed circuit boards and electronic components.
6. Have a certain understanding of SI/PI knowledge
As the output switching speed of integrated circuits increases and the density of PCB boards increases, signal integrity (SI) has become one of the issues that must be concerned in high-speed digital PCB design. Factors such as the parameters of the components and the PCB board, the layout of the components on the PCB board, and the wiring of high-speed signals will cause signal integrity problems, resulting in unstable system operation or even no operation at all. How to fully consider the signal integrity factors in the PCB design process and take effective control measures has become a hot topic in the PCB design industry today.
With the development trend of high power consumption, high density, high speed, high current and low voltage in electronic systems, the problem of power integrity (PI) in the field of high-speed PCB design has become increasingly serious.
As an excellent PCB design engineer, of course, you need to have a certain understanding of SI/PI knowledge before it can be used to guide the optimization of PCB design, improve the design of power channels, and optimize the design of decoupling capacitors.
7. Have a deep understanding of EMC/EMI knowledge of the designed product PCB
As we all know, the design of PCB must comprehensively consider various factors such as function realization, cost, production process, EMC, aesthetics and so on.
As the frequency of electronic signals and processors of electronic equipment continue to increase, electronic systems have become a complex device that contains multiple components and many sub-systems. High density and high speed will aggravate the radiation of the system, while low pressure and high sensitivity will reduce the immunity of the system. Therefore, electromagnetic interference (EMI) really threatens the safety, reliability and stability of electronic equipment. When we are designing electronic products, the design of the PCB board is very important to solve the EMI problem.