For nearly perfect pursuits, it is never endless, and the electronic design is the best illustration. 20 years ago, we have never thought that as long as you have ordered a command, the lights in the living room can light; however, now, smart home technology has made the sound control light into our daily day.
However, it is necessary to evolve such techniques, requiring the continuous improvement of electronic design to achieve "nearly perfect"; the printed circuit board technology in smart home is actually a result of many years of development and improvement.
In order to meet the advanced calculation requirements of these devices, high-speed circuits are required in dense PCB design. It is particularly important to note that the RF portion of these devices has also greatly increased the complexity of the board while increasing the functionality of the board. In order to achieve successful design, PCB designers need to balance the requirements of high-speed PCB wiring and RF PCB wiring on board. This article will discuss how to achieve this balance.
What is the key point of the high speed and RF PCB wiring?
We must comply with many specific high-speed design rules when designing a printed circuit board with high speed and RF circuits. But in any case, we are designed to "circuit board": this means that in addition to the new design parameters will be used, we must also follow all General Rules for PCB design. include:
Manufactureability Design (DFM) rules, including the assembly and test design circuit board (DFA & DFT): If our design is not constructed because of the violation of basic manufacturability design rules, we will face greater questions.
Basic PCB Design Rules for Digital, Simulation, Power and Mixed Signal Technology: Just because we need more space for high-speed trace or RF shielding, it does not mean that we can ignore routine PCB design pitch rules to squeeze together .
Heat heat dissipation problem: High-speed circuit often produces more heat, so we need to pay attention to heat dissipation than ever, and we need to ensure that our board has been cooled.
Now, our PCB design has completed settings, and has been prepared for the additional rules and constraints of high-speed and RF PCB wiring. Let's take a look at the key points of high-speed and RF PCB wiring technology.
PCB design practice contributing to high speed and RF PCB wiring
For smart home, mobile, or other Internet of the Internet, size is usually an important factor in the design. Due to the small size of the circuit boards of the high speed circuit, we need to plan accordingly to ensure that there is a space required. Some high-speed wirings may require a specific trace width to accommodate the designated ohmic value and additional spacing to minimize crosstalk.
When the high-speed and RF circuits are arranged, it is necessary to ensure that the location of the place is arranged in accordance with the signal path arranged in the schematic. The high speed circuit depends on the short direct line between the pins in the signal path, and we don't want these traces to be on the board before connectivity. On the other hand, big data and memory bus need to be equal, which usually means that some of these lines must be extended. In this case, we need to assign enough space to adjust the measured trace length to the correct value.
Another consideration is the correct Layout of the power supply and grounding network. Some devices need to be placed in a dedicated power supply or ground plane area to isolate its noise with sensitive high-speed wiring. We also need to place a bypass capacitor next to each power pin of the IC and make it as close as possible. Another key issue is to ensure that the high-speed transmission line does not pass through the power supply and ground plane splitting wiring. These traces require a continuous plane as a return path, and the split will create a canyon that cannot be traversed. This will cause EMI issues to destroy the design of signal integrity performance.
RF wiring introduces a complete set of new requirements for our way. In order to create the correct size and shape, some trace topology will be very different from us. We also need to increase additional via to shield and increase width and space, all of which require more space. Another aspect of high speed and RF design is their plate layer stack. Precisely configure the layers and materials in the superposition to support high-speed and RF microstrip and strip line wiring.
3D high speed wiring with adjustment
Whether the high speed and RF PCB wirings succeeds depends on many factors. These include compliance with high speed Layout Guide to correctly wiring high speed and RF PCB length. How to pre-plan the RF PCB wiring and simply design the basic circuit of the board (such as connecting relay in the circuit. 1881. WeChat internal link. 1882.) Is also very important. Next, let's introduce it in detail.
More details of high speed and RF printed circuit board wiring design
In order to make our high-speed or RF board design, the wiring must be performed according to the specific parameters listed below:
Close-distance observation PCB high speed layout guide
In order to successfully wiring high-speed and RF circuits in PCB, we need to follow some basic guidelines to help us avoid common problems. First, make sure our schematic contains enough information to help the Layout personnel wiring. Second, accurately understand what kind of materials and laminated structures that require high speed or RF design, so that critical design data (such as trace width and spacing) will not change in layout. The device arrangement also needs to be precise to produce a short and direct signal path, and the high-speed trace needs to follow topology modes aimed at creating the best signal integrity.
Layout skills at high speed and RF PCB
High-speed and RF traces are extremely important for optimal signal integrity performance of boards. We need to control the width to minimize the wiring impedance tolerance while maintaining sufficient spacing to prevent crosstalk. Power and ground circuitry must be away from the cracks or voids that may interrupt the signal circuit, differential pairs and measurement lines must be within their tolerance. In the design process, in order to maintain good signal integrity, the PCB designer is best to follow the design rules and constraints of the PCB design tool.
How to effectively plan and complete the RF PCB wiring
When designing a printed circuit board with a high-speed or RF circuit, we'd better plan it in advance. One of the primary goals is to determine what is the correct board layer superimposed configuration and what kind of circuit board material will be used. This will make it easy for us to design the correct impedance to control the width of the high-speed transmission line to achieve the optimal performance of the high-speed transmission line. There are many other techniques to help us design, such as providing sufficient ground plane, shielding and filtering protection for our RF circuitry.
Complete the remaining PCB design and how to connect relays in the circuit
A true problem with high speed and RF design is not enough to focus on design non-key areas. When this happens, these non-key areas may become a true problem for how other parts of the board. Therefore, we have to pay attention to basic PCB design skills, even if these skills are as simple as relays in the connection circuit.
Almost perfect PCB design requires the best PCB design tools
The design of printed circuit boards with the best high-speed and RF PCB wiring is a challenge for any designer. With standard circuit boards, we will have enough space and opportunities to optimize device arrangements, respond to power distribution network (PDN) challenges, and reduce crosstalk and noise.
Design Rule Check (DRCS) can be our helper when the high requirements signal on the board is involved. With the correct PCB design system, we can create a schematic diagram of all information required to high speed and RF design, even from the beginning to obtain the desired information.
The top system has simulation and analysis tools, which can be modeled in front of the layout, and analyze after the layout, thereby providing optimal performance for the design. Finally, we need the most powerful Layout tools. These tools should have a variety of wiring functions and a complete design rules and constraint systems, so that we are in the top of the PCB wiring technology.
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In Allegro PCB Designer Manager, management of high-speed and RF PCB wiring is very easy.
Fortunately, for all of us engaged in high-speed and RF PCB wiring projects, the above-mentioned PCB design tools have been available. Allegro PCB Designer Design Software has all the features and features we need, which can be accurately wired for high-speed and RF design, and access to a variety of different wiring functions and the latest design rules and constraint systems.
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This article is from Cadence
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