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Here you'll find insights into PCB design, tech trends, assembly issues, and trending topics
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.
The ways to control the effects of transmission line effects from the following aspects.
To do a good design, as the designer's first thing to do is to have a general overall layout, in order to make a specific design. The same pcb design is also the case, want to make the pcb board to achieve what they want, the overall layout, the placement of components is the primary consideration, they play a key role in the design of pcb board, they directly affect the entire printed circuit Board installation, reliability, ventilation, heat dissipation, wiring through rate.
In design, layout is an important part. The quality of the layout results will directly affect the effect of the wiring, so it can be considered that a reasonable layout is the first step in the success of PCB design.
At present, in the manufacture of printed circuit boards, the wires are mostly copper wires. The physical properties of the copper metal itself determine that there must be a certain impedance in the conduction process. The inductance component in the wires affects the transmission of voltage signals. The composition affects the transmission of the current signal, and the influence of the inductance is particularly prominent in the high-frequency line.
Although Protel99SE has the function of automatic layout, it can not fully meet the working needs of high-frequency circuits. It is often necessary to rely on the designer's experience. According to the specific situation, the manual layout method is used to optimize the position of some components, and then combined with automatic layout. Complete the overall design of the PCB. The rationality of the layout directly affects the life, stability, EMC (electromagnetic compatibility) of the product, etc., must be from the overall layout of the circuit board, the feasibility of wiring and the manufacturability of the PCB, mechanical structure, heat dissipation, EMI (electromagnetic Comprehensive considerations such as interference), reliability, and signal integrity.
In the design of the PCB, the anti-ESD design of the PCB can be achieved through layering, proper layout and installation. In the design process, most of the design modifications can be limited to increasing or decreasing components through prediction. By adjusting the PCB layout, ESD can be well guarded.
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:
If you find that the design experience accumulated in the previous low-speed era does not seem to work now, the same design, no problem before, but now can not work, then congratulations, you have encountered the core problem in hardware design: signal integrity . It is a good thing for you to meet one day earlier. In the past low-speed era, the signal rise time is longer when the level jumps, usually a few ns. Interconnects between devices do not affect the functionality of the circuit, and there is no need to care about signal integrity issues. But in today's high-speed era, with the increase in IC output switching speed, many are in the picosecond level, and almost all designs have encountered signal integrity problems regardless of the signal period. In addition, the pursuit of low power makes the core voltage lower and lower, 1.2v core voltage is already very common. Therefore, the noise margin that the system can tolerate is getting smaller and smaller, which makes the signal integrity problem more prominent.
There are many ways to solve EMI problems. Modern EMI suppression methods include using EMI suppression coatings, selecting appropriate EMI suppression parts, and EMI simulation design. This article starts with the most basic PCB layout and discusses the role of PCB layered stacks in controlling EMI radiation and design techniques.
During the assessment, designers must ask themselves: What scale is crucial to them? Force them to review their existing development tool capabilities and begin ordering some new features.
Many people say that pcb design is an art. This sentence is not wrong, but it is not a purely artistic appreciation but a practical art combined with electronic science. Electrical performance is always the most important pursuit of PCB design, and it is the primary goal. Do not give up electrical performance in order to pursue orderliness and beauty. But then again, PCBs that achieve the best electrical performance are generally pretty beautiful.
High-speed circuit design is a very complex design process. There are several factors that need to be considered when designing a high speed circuit. These factors are sometimes opposite each other. Such as the high-speed device layout when the position is close, although the delay can be reduced, but crosstalk and significant thermal effects may occur. Therefore, in the design, we must weigh the various factors and make a comprehensive compromise; not only meet the design requirements, but also reduce the design complexity. The adoption of high-speed PCB design means the controllability of the design process. Only controllable is reliable.
Generalization of PCB design principles (1-30)
Via is one of the important components of a multilayer PCB, and drilling costs typically account for 30% to 40% of PCB board costs.
More and more manufacturers are requesting the DC trace impedance on the PCB. The reasons for specifying and controlling the DC trace impedance are given below from the designer's point of view.
Based on the transmission line model, in summary, the transmission line will have the following effects on the overall circuit design.
With the increase of package density and the increase of operating frequency, the signal integrity problem in MCM circuit design can not be ignored. Taking the detector circuit as an example, this paper firstly uses APD software to realize the layout and layout design of the circuit, and then combines the signal integrity analysis to adjust the circuit layout and wiring structure repeatedly. The final Spectra Quest software simulation results show that the improved circuit layout and routing Meet signal integrity requirements while maintaining high simulation accuracy.
IBIS is the abbreviation of I/OBufferInformationSpecification. It is a fast and accurate method for I/OBUFFER based on I/V curve. It is an international standard that reflects the electrical characteristics of chip driver and receiver. It provides a standard file. The format is used to record parameters such as drive source output impedance, rise/fall time, and input load. It is ideal for calculation and simulation in high-speed circuit design such as oscillation and crosstalk.
Wireless signals are an integral part of many embedded systems today, and manufacturers of mobile terminals are discussing media convergence, where consumers can browse the web or watch the game in a notebook, mobile phone, portable digital TV or PDA.
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