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in the general news media as they relate to printed circuit board technology.
As experts in the manufacture and assembly of printed circuit boards, we work to make our blog a helpful resource on PCB topics and the industries that we work with, including automotive, consumer electronics, aerospace and many more.
8 Q&A in PCB Circuit Layout Design
Electromagnetic interference is caused by electromagnetic effects. As components and wiring on the PCB become more and more dense, electromagnetic interference will occur if improperly designed. In order to suppress electromagnetic interference, the following measures can be taken:
When the system is operating at 50MHz, transmission line effects and signal integrity issues will occur; when the system clock reaches 120MHz, PCBs based on traditional methods will not work unless high speed circuit design knowledge is used. Therefore, high-speed circuit design technology has become a design tool that electronic system designers must adopt. The controllability of the design process can only be achieved by using the design techniques of high-speed circuit designers.
As the current demand for speed and bandwidth for communications and computer systems continues to rise, system designers are facing a severe test. The parallel bus structure tested in time series is close to the limit of its capability, and the bus width is now over 64 bits, which makes the circuit layout extremely complicated. In addition, the large number of signals in a wide parallel bus are also very cumbersome to synchronize, especially as these signals are subject to random factors such as noise and crosstalk.
When I saw the PCB of a computer motherboard, I thought I was able to draw a great thing myself. Later when touched protel99se and entered the drawing board team, followed by Altium, Cadence, and so on. As the experience of the drawing board accumulated, more and more issues were noticed. A good PCB board is not only connected to the line.
The abstract and complicated digital high-speed logic principle, how to transmit the square wave signal in the transmission line, and how to ensure its signal integrity (Signal Integrity), reduce the noise of its noise (Noise) and other professional expressions, if simple The example of life is explained, but instead of moving a bunch of mathematical formulas and difficult physics language, it is the inspiration and benefit for novices or interlocutors.
PCB Best Design Methodology: Six things to consider when passing a PCB schematic to a layout design. All examples mentioned in this article were developed using the Multisim design environment, but the same concepts apply when using different EDA tools.
To popularize LED lamps, it is necessary not only to significantly reduce costs but also to solve technical problems. How to solve the problems of energy efficiency and reliability, Doug Bailey, vice president of marketing for Power Integrations, shared the experience of efficient and reliable LED driver design.
The schematic design before single-panel proofing is a preliminary preparation work. When drawing a schematic diagram, it is necessary to pay attention to the final connection of each file as a whole in the hierarchical design. This also has important significance for the future work. Due to software differences, some software may appear to be physically connected (electrically). If you do not use related detection tools to detect, if something goes wrong, it will be too late to wait until the board is ready. Therefore, it is important to emphasize the importance of doing it in order, and we hope to draw everyone’s attention.
PCB design needs to set different points in different stages. In the layout stage, large grid points can be used for device layout.
1. What is Signal Integrity?
Regarding signal integrity issues, when the system clock exceeds 50 MHz, the signal interconnect on the board introduces signal delays on the timing path, and these signal delays constrain the performance of the board-level design. How the transmission line effect will quickly introduce serious signal integrity issues like signal oscillation, overshoot and undershoot, and how these issues will threaten the noise tolerance of the design and the monotonic consistency principle of the design.
The design of the high-frequency circuit PCB is a complicated process, and many factors involved may directly affect the performance of the high-frequency circuit. Therefore, designers need to continuously research and explore in the actual work, accumulate experience, and combine the new EDA (Electronic Design Automation) technology to design high-performance circuit PCB with excellent performance.
From a battery point of view, once the design engineer connects the battery leads to the front end of the transmission line, there is always a constant value of current flowing out of the battery and keeping the voltage signal constant. Some people may ask, what kind of electronic components have such behavior? A constant current value is maintained when a constant voltage signal is added, of course the resistance.
As the PCB size requirements are getting smaller and smaller, device density requirements are getting higher and higher, and PCB design is becoming more and more difficult. How to achieve a high PCB layout rate and shorten the design time, careful analysis of the design and careful setup of the tool software before starting the wiring will make the design more in line with the requirements.
Since the printed circuit board is not a general end product, the definition of the name is slightly confusing. For example, the motherboard for the personal computer is called the motherboard and cannot be directly called the circuit board. Although there is a circuit board in the motherboard, It's not the same, so when you evaluate the industry, you can't say the same thing. For example, because there are integrated circuit parts on the board, the news media called him an IC board, but in fact he is not equivalent to a printed circuit board.
PCB wiring requirements to avoid one of the cases is the right-angle alignment. In principle, right-angle alignment changes the line width of the transmission line, resulting in discontinuities in impedance. In fact, not only the right-angle alignment, angle, acute angle alignment may cause impedance changes.
There are many simulation tools for analyzing signal integrity, each with its own characteristics.
In the design of power circuit, electromagnetic interference is one of the key factors affecting product performance. At present, there are many ways to solve the problem of EMI for engineers. Generally, methods for suppressing EMI include: EMI suppression coating, EMI simulation. Design and selection of suitable EMI suppression parts. This article will start with the PCB, and introduce the role and design skills of PCB layered stacking in controlling EMI radiation.
To get the best performance from an electronic circuit, the board is the support for the circuit components and devices in the electronics. Even if the schematic design of the circuit is correct and the printed circuit board is not properly designed, it will adversely affect the reliability of the electronic product. When designing a printed circuit board, it is important to use the correct method, follow the general principles of PCB design, and conform to the requirements of the anti-jamming design and the layout of the wires. In order to design a PCB of good quality and low cost, the following general principles should be followed:
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