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.
Signal integrity (SI) issues are becoming a growing concern for digital hardware designers. Due to the increased data rate bandwidth in wireless base stations, wireless network controllers, wired network infrastructure, and military avionics systems, board design has become increasingly complex.
This article focuses on signal integrity challenges involving high-speed interface design (the main features of RapidIO switching support these high-speed interface designs), and the ability to optimize RapidIO switching is designed to achieve high signal integrity in high-speed designs.
9 basic knowledge discussions about grounding technology
The advantage of Protel is that it is more popular in the Chinese market. As long as the PCB is Protel, any file can make a board. Southern China is more likely to accept the OrCAD format.
The main cause of electromagnetic interference caused by the ground line is the impedance of the ground line. When the current flows through the ground line, a voltage is generated on the ground line. This is the ground line noise. Driven by this voltage, ground loop current is generated, causing ground loop interference. When two circuits share a ground line, a common impedance coupling is formed. The method for solving the ground loop interference is to cut the ground loop, increase the impedance of the ground loop, and use a balanced circuit. The solution to the common impedance coupling is to reduce the impedance of the common ground portion or to use a parallel single-point grounding to completely eliminate the common impedance.
The ways to control the effects of transmission line effects from the following aspects.
When the system is operating at 50MHz, transmission line effects and signal integrity issues will occur; when the system clock reaches 120MHz, PCBs based on traditional methods will not work unless high speed circuit design knowledge is used. Therefore, high-speed circuit design technology has become a design tool that electronic system designers must adopt. The controllability of the design process can only be achieved by using the design techniques of high-speed circuit designers.
As circuit design becomes more complex and high-speed, how to ensure the integrity of various signals (especially high-speed signals), that is, to ensure signal quality, becomes a problem. At this time, it is necessary to analyze by means of the transmission line theory, and the characteristic impedance matching of the control signal line becomes the key. The non-strict impedance control will cause considerable signal reflection and signal distortion, resulting in design failure. Common signals, such as PCI bus, PCI-E bus, USB, Ethernet, DDR memory, LVDS signals, etc., require impedance control. Impedance control ultimately needs to be realized through PCB design, and higher requirements are also imposed on the PCB board process.
26. When there are multiple digital/analog function blocks in a PCB board, the conventional practice is to separate the digital/analog grounds. What are the reasons?
Can you introduce some foreign technical books and materials on high-speed PCB design?
1. How to choose PCB board?
Each VXI bus device has a set of “configuration registers”. The system main controller reads some of the basic configuration information of the VXI bus device by reading the contents of these registers, such as device type, model, manufacturer, and address space (A16, A24). , A32) and the required storage space.
With the development of modern wireless communication systems, communication systems such as mobile communication, radar, and satellite communication have higher requirements on the switching speed, power capacity, and integration of the transceiver switch. Therefore, research on VXI bus technology and development meets the military. The special requirements of the VXI bus module is of great significance. We will use the virtual instrument idea to implement the hardware circuit in software. The RF switch designed below can be directly controlled by the computer, which can be easily connected with the VXI bus test system. Integration, to maximize the use of computer and microelectronics technology in today's testing field, has broad prospects for development.
PCB interconnect design techniques include testing, simulation, and various related standards, where testing is the method and means to verify the results of various simulation analyses. Excellent test methods and means are necessary to ensure the analysis of PCB interconnection design. For traditional signal waveform testing, the main focus should be on the length of the probe leads to avoid unnecessary noise introduced by Pigtail. This article focuses on new applications and development of interconnect testing techniques.
High-speed and high-density has gradually become one of the significant development trends of many modern electronic products. High-speed and high-density PCB design technology has become an important research field.
The interconnection of the board system includes: chip-to-board, interconnection within the PCB, and three types of interconnections between the PCB and external devices. In the RF design, one of the main problems facing the electromagnetic characteristics engineering design at the interconnection point, this paper introduces the various techniques of the above three types of interconnection design, including the device installation method, wiring isolation and measures to reduce lead inductance.
Since SMT generally uses infrared furnace heat flow welding to achieve component soldering, the layout of the components affects the quality of the solder joints, which in turn affects the yield of the product. For the design of RF circuit PCB, electromagnetic compatibility requires that each circuit module does not generate electromagnetic radiation as much as possible, and has certain anti-electromagnetic interference capability. Therefore, the layout of components directly affects the interference and anti-interference ability of the circuit itself. This is also directly related to the performance of the designed circuit.
With the development of communication technology, handheld wireless RF circuit technology is used more and more widely, such as: wireless pager, mobile phone, wireless PDA, etc., the performance indicators of the RF circuit directly affect the quality of the entire product. One of the biggest features of these handheld products is miniaturization, and miniaturization means that the density of components is large, which makes the mutual interference of components (including SMD, SMC, die, etc.) very prominent.
In the design of electronic systems, in order to avoid detours and save time, the anti-interference requirements should be fully considered and avoided, and remedial measures against interference should be avoided after the design is completed. There are three basic elements that form interference: