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support@nextpcb.comHere 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.
As an electronic engineer, designing a circuit is a must-have hard work, and the principle design is perfect. If the board design is unreasonable, the performance will be greatly reduced, and even if it is serious, it will not work properly.
How to reduce the mutual interference between digital signals and analog signals?
To address signal integrity issues, the entire design process needs to be further upgraded to become a complete set of tools that can take into account multiple different effects and design assessments.
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. Although the direct result of circuit design is manifested in signal integrity, we must not neglect the power integrity design. Because power integrity directly affects the signal integrity of the final PCB. Both power integrity and signal integrity are closely related, and in many cases, the main cause of signal distortion is the power system. For example, the ground bounce noise is too large, the design of the decoupling capacitor is not suitable, the loop effect is serious, the division of multiple power/ground planes is not good, the design of the ground layer is unreasonable, the current is not uniform, and the like.
Now that we know that PCBs can provide mechanical support and electrical connections for electronic components, how are these electronic components mounted on the PCB?
In order to successfully latch data into the device, the data signal must remain active at the input of the receiving chip for a sufficient amount of time to ensure that the signal is correctly latched by the clock sample. This time is called hold time. In the common clock bus, the receiver buffer latches the data with the second clock edge while latching the next data to the data transmitter on the driver side. Therefore, in order to satisfy the receiving end holding time, it is necessary to ensure that the valid data is latched into the receiving terminal flip-flop before the next data signal arrives, which requires that the delay of receiving the clock CLKA is smaller than the delay of receiving the data signal.
Can you introduce some foreign technical books and materials on high-speed PCB design?
10 questions and answers.
People think that the earth can absorb all the charges, always maintain a stable, is the ultimate reference point. Although some boards are not connected to the earth, but the power plant is connected to the earth, the power of the board will eventually return to the power plant into the ground.
For chip design, there are usually two ways to solve signal integrity problems. The RF solution focuses on the transmission line, often using impedance matching on the package boundary, while the digital (ie, broadband) solution emphasizes the choice of package, controlling the number of simultaneous switching and switching speed, and using between the external power supply pins of the package and ground. Bypass capacitors, the capacitance inside the IC is achieved by the overlap of the metal layers, which provides a local low-impedance path for high-speed transient currents to prevent ground bounce.
At present, electronic equipment is still used in printed circuit boards as the main assembly method for various electronic devices and systems. Practice has proved that even if the circuit schematic design is correct, improper design of the printed circuit board will also have an adverse effect on the reliability of electronic equipment. For example, if the two fine parallel lines of the printed board are in close proximity, a delay in the signal waveform is formed, and reflection noise is formed at the end of the transmission line. Therefore, when designing a printed circuit board, it should be noted that the correct method is used.
The following is an introduction to the testing experience and methods of resistors.
10 techniques
The process is as shown below: (PCB/LCD design)-->(CAM system)-->(Gerber file)
1. The information received is completed (including: schematics, *.brd, bill of materials, PCB design and change requirements, standardization requirements, process design documents)
The frequency measurement is generally performed by a scanning spectrum analyzer, which scans the amplitude of each frequency signal and stores it under a certain resolution bandwidth (RBW), thereby displaying the information of the amplitude as a function of the entire frequency band. The RBW is an important consideration for scanning spectrum analyzers to provide excellent dynamic range and high accuracy of the static spectral components of the signal. However, the main disadvantage of a scanning spectrum analyzer is that it tests the amplitude of a frequency point of the signal only at one point in time.
PCB material are divided into: 94HB, fireproof board (94VO, FR-1, FR-2), semi-glass (22F, CEM-1, CEM-3), and full glass (FR-4).
At first glance, the PCB is similar in appearance regardless of its inherent quality. It is through the surface that we see the differences that are critical to the durability and functionality of the PCB throughout its lifetime.
Many people are very vague about the concept of the critical length of the lines on the PCB. Even many people don't even know the concept. If you design a high-speed circuit board but don't know the concept, you can be sure that the final board may not work stably. And you are confused, you can't start debugging.
For the most basic PCB, the components are concentrated on one side, and the wires are concentrated on the other side. Because only one side can be wired, we call this PCB a single panel. Both sides of the double panel can be routed, so the wiring area is twice as large as that of a single panel, making it suitable for use on more complex circuits.
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