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.
PowerPCB provides users with a quick set of commands. Shortcut commands are mainly used for operations that require frequent changes to the settings during the design process. For example, changing the line width, wiring layer, and changing the design Grid can be achieved by shortcut commands.
Whether the wiring of a printed board can be completed smoothly depends mainly on the layout, and the higher the density of the wiring, the more important the layout. Almost every designer has encountered such a situation. When there are only a few wires left, they find that they can't be laid out anyway. They have to delete a lot or all of the wiring and re-adjust the layout! A reasonable layout is guaranteed. The premise of wiring.
The core part of the PCB design method based on signal integrity computer analysis is the establishment of the PCB board level signal integrity model, which is the difference from the traditional design method. The correctness of the SI model will determine the correctness of the design, and the establishability of the SI model determines the feasibility of this design method.
In order to perform circuit simulation, it is necessary to first build a model of the component, that is, for the various components supported by the circuit simulation program, there must be a corresponding mathematical model to describe them in the simulation program, that is, a calculation formula that can be calculated by a computer. To express them. An ideal component model should reflect both the electrical characteristics of the component and the numerical solution on the computer. In general, the higher the accuracy of the device model, the more complex the model itself, and the more the number of model parameters required. In this way, the amount of memory occupied increases and the calculation time increases. While integrated circuits often contain a large number of components, a slight increase in the complexity of the device model can double the computation time. Conversely, if the model is too rough, the analysis results will be unreliable. Therefore, the complexity of the component model used depends on actual needs.
The range of variations in characteristic impedance control must consider four factors:
The characteristic impedance of the multi-layer signal transmission line, Z0, currently requires a control range of typically 50 Ω ± 10%, 75 Ω ± 10%, or 28 Ω ± 10%.
When PCB layout is performed, it often happens that when a trace passes through an area, due to the limited wiring space of the area, thinner lines have to be used, and after passing through this area, the line is restored to its original width. A change in the width of the trace causes a change in impedance, so reflection occurs and affects the signal. So under what circumstances can this effect be ignored, and under what circumstances must we consider its impact?
The components should be arranged in a straight line in the order of the electrical schematics, and the compactness is required to shorten the length of the printed conductors and achieve a uniform assembly density. Under the premise of ensuring electrical performance requirements, the components shall be parallel or perpendicular to the board surface and parallel or perpendicular to the main board edge. It is evenly distributed on the board surface.
Four designs and steps and methods
Starting from the improvement of system electromagnetic compatibility, combined with the characteristics of hybrid integrated circuit technology, the problems that should be paid attention to and the specific measures taken in the design of hybrid integrated circuits are proposed.
In the circuit design, often only pay attention to improve the wiring density, or pursue uniform layout, ignoring the influence of the line layout on preventing interference, causing a large number of signals to radiate into the space to form interference, which may lead to more electromagnetic compatibility problems. Therefore, good wiring is the key to success in design.
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.
There are two ways to route: automatic routing and interactive wiring.
As device operating frequencies become higher and higher, the signal integrity issues faced by high-speed PCB design become a bottleneck in traditional design, and engineers face increasing challenges in designing complete solutions. Although the high-speed simulation tools and interconnect tools can help designers solve some of the problems, high-speed PCB design requires more experience and deep communication between the industry.
The differential signal pairs with very close wirings are also closely coupled to each other. This mutual coupling reduces EMI emissions. The main disadvantage of differential signal lines is the increased PCB area. This paper introduces the circuit board design process. Wiring strategy for differential signal line routing.
In circuit design, we are generally concerned about the quality of the signal, but sometimes we are often limited to the signal line for research, and the power and ground as the ideal situation to deal with, although this can simplify the problem, but in high-speed design This simplification is no longer feasible.
How to reduce the mutual interference between digital signals and analog signals?
(1) The design of the circuit schematic: The design of the circuit schematic is mainly the PROTEL099 schematic design system (AdvancedSchematic) to draw a circuit schematic. In this process, we should make full use of the various schematic drawing tools and various editing functions provided by PROTEL99 to achieve our goal, that is, to obtain a correct and exquisite circuit schematic.
In this article,I will tell you a new way to solve the problem of high speed singal 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.
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