Knowledge architecture of printed circuit board design

Printed circuit board design is a key link in electronic product design and an important carrier of electronic products. A good printed circuit board 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, maintenance and certification. Then, as an excellent PCB engineer, he should have the following knowledge structure:

1. Familiar with at least one industry mainstream EDA tool.

There are many kinds of printed circuit board design software. At present, the following are used in the market: cadenceallegro, mentor EE, mentor pads, altiumdesigner, PROTEL, etc., of which cadenceallegro has the highest market share.

Allegro has many advantages, such as friendly software operation interface, fast response block, high operation efficiency, rich secondary development functions, perfect rule manager functions, high-speed design, powerful exclusive functions, etc. It supports large projects and will not greatly reduce the response speed due to the increase of design scale. There will be little pressure to use Allegro for tens of thousands of pin design projects. Therefore, it is very suitable for communication industry, commercial server, industrial control, military industry and other industries.

2. Be familiar with equipment, read circuit schematic diagram and recognize key signals.

Common electronic components: resistance, capacitance, inductance, transformer, diode, triode, FET, optocoupler, sensor, crystal oscillator, relay, buzzer, rectifier bridge, filter, switch, fuse, etc.

Key signals include: power supply, analog signal, high-speed signal, clock signal, differential signal, synchronization signal, etc.

3. Familiar with the production process and technology of several common plates and circuit board factories.

Common board: paperboard, semi fiberglass board, fiberglass -4 fiberglass board, aluminum substrate, etc.

4. Be familiar with the assembly process and process of patch insert.

Key knowledge: Surface Mount Technology (SMT), perforation Mount Technology (THT), etc.

5. Familiar with welding test

The welding performance test is basically used for qualitative and quantitative evaluation of the welding performance of parts, printed circuit boards, solders, fluxes, etc. In the assembly and welding technology of electronic products, the welding quality directly affects the overall quality of machinery. Therefore, in order to improve the welding quality, we should not only strictly control the technical parameters, but also scientifically test the welding performance of printed circuit boards and electronic components.

6. Have a certain understanding of Si / PI knowledge

With the increase of the output switching speed of integrated circuits and the density of printed circuit boards, signal integrity (SI) has become one of the essential problems in the design of high-speed digital printed circuit boards. The parameters of components and printed circuit boards, the layout of components on printed circuit boards, the wiring of high-speed signals and other factors will lead to signal integrity problems, resulting in unstable or even no operation of the system. How to fully consider the signal integrity factors and adopt effective control measures in the design process of printed circuit board has become a hot topic in the printed circuit board design industry.

With the development of electronic systems with high power consumption, high density, high speed, high current and low voltage, the problem of power integrity in the field of high-speed printed circuit board design is becoming more and more serious.

As an excellent PCB Design Engineer, of course, you need to have a certain understanding of Si / PI knowledge to guide the optimization of PCB design, the improvement of power channel, the optimization of decoupling capacitor and so on.

7. In depth understanding of EMC / EMI knowledge in designing product PCB.

The design of PCB shall comprehensively consider the factors such as function realization, cost, production process, EMC, beauty and so on.

With the continuous improvement of electronic signal and processor frequency of electronic equipment, electronic system has become a complex equipment, including multiple components and subsystems. High density and high speed will aggravate the radiation of the system, while low voltage and high sensitivity will reduce the anti-interference ability of the system. Therefore, electromagnetic interference (EMI) does threaten the safety, reliability and stability of electronic equipment. When we design electronic products, the design of PCB is the most critical to solve the EMI problem.