Must be PCB circuit board laminate class problems confused everyone for a long time, and engineers discussed for a long time, to write this article. We list some common problems of PCB laminate and related solutions. If you encounter a common problem such as PCB board laminate, you should formulate a standard, and later encounter such problems can be the right medicine.
1. The flow direction should be scientific and reasonable
There are many aspects involved in this point, such as high voltage/low voltage, input/output, strong/weak data signals, high frequency/low frequency and so on. Their flow is most reasonable should be linear, should not merge with each other. It follows the principle of eliminating dry scratching between each other. A more suitable flow direction is in a straight line, but it is difficult to achieve. The worst direction is a loop, and thankfully there is an isolation operation. If it is specifically aimed at DC, the low-voltage PCB design requirements can be lower. Therefore, the so-called "scientific rationality" is only relative.
2, the power filter/decoupling capacitor layout is reasonable
The layout of the PCB board is critical to the appearance and performance of the entire circuit board. Only some of the power filter/decoupling capacitors are drawn in the schematic, but it is not specified where they are to be connected. I think that those capacitors are set for switching devices or other components that need to use filtering/decoupling, the position of the capacitor should be sure to rely on those components, and the effect will not be found at a long distance. When we scientifically and reasonably power filter/decouple the capacitor, the common problems of the ground point no longer seem prominent. You can try it!
3. Good ground point
I don't need to tell you how important it is to pick a landing spot. It has been discussed by countless professionals and generally requires a standard common point. For example, the multiple ground lines of the forward amplifier should be merged and then connected to the main line ground and so on. However, in real life, it is difficult to do it completely due to various types of restrictions. But we cannot ignore it and should do our best to follow the principles. This common problem is very flexible in practice, and different people have different solutions. If it can be expressed specifically for specific pcb boards, it is very easy to understand.
4. Reasonable line selection
Call the circuit board, the line is of course very important drop! Make the lines as wide as possible. High voltage and high frequency lines should be smooth, no sharp chamfer. It should not be 90° at the bend, and the ground wire should be as wide as possible. If you want to solve the problem of ground point, the best way is to cover a large area of copper.
The problems of PCB circuit boards are inseparable from the design and circuit board processing. For example, sometimes the problems that appear in post-production are likely to be caused by the PCB design. For example, too many line holes, substandard copper sinking process, and so on, it is easy to hide a lot of security risks. From the above problems we can draw a conclusion that in the PCB design concept should be as much as possible to reduce the line hole. If the number of parallel lines in the same direction is large and the density is large, it will be connected together when welding. Therefore, the welding level at the time of production determines the size of the line density. The spacing of solder joints is too small, and the difficulty of manual welding is increased a lot, and the only way to solve the welding quality is to reduce the work efficiency. Otherwise, the problems will become more and more difficult to deal with. The level and efficiency of the welder determines the narrowest spacing of the solder joints.
When the pad or through the hole size is too small, it is more difficult for manual drilling. When the size of the pad does not match the size of the drilling hole, it is a bolt from the blue for CNC drilling, and the pad is easy to be C-shaped. The pads can be drilled out in serious cases. If the wire is too thin, and there is no copper in the large-scale unwired area, there is likely to be uneven corrosion. That is to say, after corroding the unwired area, it is likely to excessively corrode the thin wire. Sometimes it looks like the wire is broken but it's not, and in the worst cases it will be. Therefore, the setting of copper is not only to expand the ground area.
PCSPCB is a manufacturer specializing in PCB board, FPC board, film switch panel. The main products are: PCB circuit board, FPC flexible circuit board, film switch, film panel, acrylic panel and other products, the company has a vigorous, professional and experienced technical, production and management team, with advanced printed board special production and testing equipment, a standardized operation system, so that the internal operation is more accurate and efficient, the external service is more systematic and timely. Create greater value for customers.
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