Article 1 PCB cablingIn PCB design, wiring is an important step to complete the product design. It can be said that the previous preparations are for it. In the entire PCB, wiring is the most restrictive in the design process, the skills are the finest and the workload is the greatest. PCB wiring includes single-sided
4-layer PCB design (based on AD)
Reprinted from:Http://blog.sina.com.cn/s/blog_982d7fa301019f21.html
tag: miscellaneous
category: technical _ hardware
Among the many operating layers provided by the system, there are two layers of electrical layers, namely the signal layer and the inner layer. These two layers have completely different properties and usage methods.
The signal layer is called the front-slice
Ctrl+end tune to 0.
Q switch mm and mil
Ctrl+q/////o+b "Separately according to the" British metric system Switch-----"8 detailed said"
0805 stands for length 80mil width 50mil of which 1mil=10 minus three square inches, 1 inches =25.40mmThat's 0805 of the length is about 2.0MM and the width is about 1.27MM.
V+f display of all PCB components
Top overlay Layer (note), similar to the wiring inside the pad
"Align": check-right-click-align-align bottom
Summary of PCB multilayer Design
Reprinted: PCB multi-board design suggestions and examples (, 12)
Design requirements:
A. The component plane and welding plane are complete ground planes (shielded );
B. There is no adjacent parallel wiring layer;
C. All signal layers should be adjacent to the ground plane as much as possible;
D. The key signal is adjacent to the formation and does not span the
Definition of PCB layer:Solder Mask: Solder masks, refers to the board on the green oil on the part, because it is negative output, so actually there is solder mask part of the actual effect is not on the green oil, but tin plating, silver.
Help solder layer: Paste mask, is the machine to use the patch, is corresponding to all SMD components of the pad, the size and Toplayer/bottomlayer layer, is used to open the steel network leakage tin.
Key points:
We all know that PCB is to turn the designed schematic diagram into a real PCB Board. Please do not underestimate this process. There are many things that work in principle that are hard to implement in the project, or what others can achieve, but others cannot. Therefore, it is not difficult to do a PCB, but it is not easy to do a PCB.The two major difficulties
Allegro PCB design experience
1. When components are encapsulated, what is the pin number defined for a pad without an electrical connection?Answer: when placing a pad, select Mechanical.
2. How to add tears in allegro?A: You must first open all the cabling layers and execute the command route-> gloss-> parameters .., in the displayed dialog box, click pad and T connection fillet, click the square on the left, and click circular pads, pins, vias,
Before designing a multilayer PCB, the designer must first determine the structure of the PCB based on the circuit size, circuit board size, and EMC requirements, that is, it is decided to adopt a 4-layer, 6-layer, or more layers of the circuit board. After determining the number of layers, determine the placement location of the inner electrical layer and how different signals are distributed on these laye
After the schematic design, the drawing board is required. a pcb file is required. There are several ways to generate a PCB file:
1. directly use File> New> PCB in the toolbar to create a PCB, as shown in figure
2. Another better method is to use the PCB generation wi
ArticleDirectory
10 C
20 C
30 C
Copper
Trace width
Maximum current amps
Inch
Mm
Relationship between PCB width and current Reprinted from: http://www.dianyuan.com/article/207334, calculation method is as follows:
First, calculate the cross-sectional area of the track. The thickness of most PCB copper foil is 35um (if you are not sure, you can ask the
post.
Add the package , in the schematic, in the DSN file right-click, select Editor Object property, check the PCB footprint This column is not the package of each device has been filled in, and is not corresponding to the schematic diagram. If that's the case, it's a big part of the success.
The final check checks, you can generate network tables ,DSN files, Tools---Create netlist, generate the device package and schematic one by one corresponding
First, the circuit design of the advance work1, draw schematic diagram with schematic design tool, and generate corresponding network table. Of course, some special cases, such as the circuit version is relatively simple, already have a network table and other circumstances can not be schematic design, directly into the PCB design system, in the PCB design system, you can directly take the part package, man
The testability concept of PCB DesignThe testability of the product design (De sign for testability. OFT) Product manufacturability is also the main content from the production point of view is also one of the design process. It refers to the design of the product performance can be considered difficult to detect, that is, design products should consider how to use the simplest method of product performance and processing quality testing, or product d
Recently, after drawing a four-rotor PCB, I want to print it on A4 paper to see if the device is properly placed. Because my computer is not connected to the print sister, I can't print it directly, the intelligent PDF file of AD is used to print the Board files in pdf format. The result is that the printed board is enlarged and the original proportion is lost. In this way, the meaning of printing is lost. Later, I found a convenient method, in AD fil
(Voltage Adjustment Integrated Block Component Library)
Protes Dos Schematic Zilog. Lib (Z80 series CPU Integrated Block Component Library produced by Qi Ge)
II,PCBAspect:
1,The basic process for making PCB:
After importing the network table, set the mesh size-> draw a roughly closed physical boundary on the Keepover Layer (which can be adjusted later)-> draw a mechanical positioning hole (Aperture 3mm, the hole center is 5.08mm away from the edg
, when the clock frequency exceeds 100 MHz or the rising edge is less than 1 ns, the signal integrity effect becomes important.
In PCB, the signal line is the main carrier for signal transmission. The cabling of the signal line directly determines the superior signal transmission, thus directly affecting the performance of the entire embedded system. Unreasonable wiring will seriously lead to various signal integrity problems, and generate timing, noi
1-2 is omited, for more detail please referWww.usb.org.
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3 layout guidelines
3.1 General Routing and placementUse the following general routing and placement guidelines when laying out a new design. TheseGuidelines will help to minimize signal quality and EMI problems. The high speed USB validation effortsFocused on a four-layer motherboard where the first layer is a signal layer, the second layer is power,Third layer is ground and the fourth is a signal layer. This results in placing mos
During circuit design, there are more and more power supplies and multiple locations on a PCB, such as 48 V, 12 V-Common types of power supplies such as 12 V, 5 V,-5 V, 3.3 V, 2.5 V, 1.8v1.v, agnd (analog location) dgnd (Digital location), pgnd (Protected Area) the ground plane required for different functions, some IC clearly requires the single point grounding, and the required power supply, ground plane hollowing. In order to ensure high reliabilit
When drawing a PCB, you often need to check the corresponding components on the schematic. If the number of components is small, you can find them. Also, alicloud designer provides a good cross-search function.
Here I suggest using two monitors, one with a schematic diagram and the other with a PCB, which makes it easier to find out.
1 use the shortcut key T + c
This shortcut key is used in both the schem
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