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.
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.
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.
In the PCB design, wiring is an important step to complete the product design. It can be said that the previous preparation work is done for it. In the whole PCB, the wiring design process is the highest, the trick is the finest, and the workload is the largest. The PCB wiring has single-sided wiring, double-sided wiring, and multilayer wiring. There are two ways to route: automatic routing and interactive wiring. Before automatic routing, you can use interactive pre-wired lines that require more stringent requirements. The edges of the input and output should avoid adjacent parallel to avoid reflection interference. If necessary, ground wire should be isolated. The wiring of two adjacent layers should be perpendicular to each other, and parasitic coupling is easy to occur in parallel.
Layer setting and power ground segmentation requirements; Power module requirements
Thermal design requirements for layout; Layout signal integrity requirements; EMC requirements
Flexible printed circuit boards can be classified according to the type of bending encountered during assembly and use. There are two design types, which are discussed below:
For digital circuit designers, the inductance of the via is more important than the capacitance. Each via has a parasitic mid-inductance. Because the physical structure of the via is small, its characteristics are very lumped lumped circuit components. The main effect of the series inductance of the via is to reduce the effectiveness of the power supply bypass capacitor, which will make the overall power supply filtering effect worse.
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.
Qualifications and main duties.
In a company, from a product-level perspective, what are the prerequisites for a signal integrity engineer, what they are doing, and a bystander's understanding is as follows:
The characteristic impedance of the control signal transmission path is kept constant, and the reflection coefficient is 0, which means that there is no reflection on the transmission path. This is called impedance matching. At this point the signal will be ideally delivered to the terminal.
The following layered stacking scheme assumes that the supply current flows on a single layer, with single or multiple voltages distributed across different parts of the same layer. The case of multiple power planes is discussed later.
There are many ways to solve EMI problems. Modern EMI suppression methods include: using EMI suppression coatings, selecting suitable EMI suppression components, and EMI simulation designs. This article starts from the most basic PCB layout and discusses the role of PCB layered stacking in controlling EMI radiation.
Digital devices are moving in the direction of high speed, low consumption, small size, and high anti-interference. This trend has put forward many new requirements for the design of printed circuit boards. The application of Protel software in China is quite common. However, many designers only pay attention to the Protel software's routing rate. The improvements made by Protel software to adapt to the changes of device characteristics are not used in the design, which not only makes software resources. The waste is more serious, and the excellent performance of many new devices is difficult to play. This paper intends to introduce Protel for Windows V1.5 software as an example to introduce the high-frequency circuit wiring when Protel software can Some special countermeasures are provided.
We can derive the value of the characteristic impedance, which is the value of the instantaneous impedance seen by the signal during transmission.