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.
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.
Designers may design odd-numbered printed circuit boards (PCBs). If the wiring does not require an extra layer, why use it? Isn't reducing layers not making the board thinner? If the board is one less layer, is the cost lower? However, in some cases, adding a layer will reduce the cost.
A number of issues that should be noted for PCB board reliability design in high speed DSP systems.
This article will show you how to avoid those hidden but common mistakes, and introduce a few tips to help engineers discover hidden errors in PCB copy board software. Most software development projects rely on code inspection, structural testing, and functional testing to identify software defects. Although these traditional techniques are very important and can find most software problems, they cannot detect many common errors in today's complex systems.
In any power supply design, the physical design of the PCB is the last link. The design method determines the electromagnetic interference and power supply stability. Let's analyze these links in detail:
PCB is a support for circuit components and devices in electronic products. It provides electrical connections between circuit components and devices. With the rapid development of electricity technology, the density of PGB is getting higher and higher. PCB design has a great impact on the ability to interfere with interference. Therefore, when designing PCBs. The general principles of PCB design must be followed and should meet the requirements for anti-interference design.
The direct cause of the temperature rise of the printed board is due to the existence of circuit power consumption devices. The electronic devices have different degrees of power consumption, and the heat generation intensity varies with the power consumption.
The heat generated during the operation of the electronic device causes the internal temperature of the device to rise rapidly. If the heat is not dissipated in time, the device will continue to heat up, and the device will fail due to overheating, and the reliability of the electronic device will decrease. Therefore, it is very important to dissipate the board.
At present, electronic equipment is used in various electronic devices and systems, and printed circuit boards are still the main assembly method. Practice has proved that 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 device. For example, if the two thin parallel lines of the printed board are in close proximity, a delay in the signal waveform is formed, and reflected noise is formed at the end of the transmission line. Therefore, when designing a printed circuit board, care should be taken to use the correct method.
Under normal PCB design conditions, the following factors are mainly affected by PCB manufacturing:
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.