The five key points of double-layer PCB circuit board planning are:

1. There should be a reasonable direction

Such as input/output, AC/DC, strong/weak signals, high/low frequency, high/low voltage, etc. Their direction should be linear (or separated) and should not blend with each other, with the intention of avoiding interference with each other. The best direction is in a straight line, but it is generally not easy to complete. The most unfavorable direction is in a circular shape. Fortunately, isolation can bring improvement. The requirements for PCB planning for all DC, small signal, and low voltage can be lowered. So 'reasonable' is relative.

2. Choosing a good delivery address: The delivery address is often the most important

I don't know how many engineering and technical personnel have discussed this small address, which shows its importance. In general, it is required to have a common ground point, for example, multiple ground lines of the forward amplifier should converge before being connected to the main ground line, and so on. In reality, it is difficult to fully achieve due to various limitations, but efforts should be made to comply. This problem is appropriately sensitive in practice, and everyone has their own set of solutions. If it can be explained in detail for the circuit board, it will be easy to understand. You can also enter and learn about the related article "How to Plan the Grounding of PCB Board".

3. Reasonably install power filter/decoupling capacitors

Generally, only a few power filter/decoupling capacitors are shown in the schematic diagram, but it is not indicated where they should be connected to each other. In fact, these capacitors are designed for switching devices (gate circuits) or other components that require filtering/decoupling. When placing these capacitors, they should be placed as close as possible to these components, as being too far away will have no effect. It is interesting that when the power filter/decoupling capacitor is properly placed, the issue of grounding address becomes less significant.

4. There are requirements for the diameter of the lines, and the size of the buried holes and through holes should be appropriate

If conditions permit, a wide line should never be made thin; High voltage and high-frequency wires should be smooth and free from sharp chamfers, and right angles should not be used for bends. The ground wire should be as wide as possible, and it is best to use large-area copper plating, which can significantly improve the address problem. The size of the solder pad or wire hole is too small, or the size of the solder pad does not match the size of the drill hole properly. The former is unfavorable for manual drilling, while the latter is unfavorable for CNC drilling. Simply drill the solder pads into a "c" shape, and if heavy, drill off the solder pads. The wire is too thin, and the large area without wiring is not covered with copper, which simply causes uneven corrosion. After the corrosion of the un wired area is complete, the thin wires are likely to corrode too much, or appear to break but not completely, or completely break. So, the effect of setting copper deposition is not only to increase the ground area and resist interference.

5. Number of vias, solder joints, and line density

Some problems are not easily discovered in the early stages of circuit manufacturing, and they often appear in the later stages, such as too many wire holes and a slight carelessness in the copper deposition process, which can bury dangers. So, in the planning, the number of cable holes should be minimized as much as possible. The density of parallel lines in the same direction is too high, making it easy to connect them together during welding. So, the line density should be determined based on the level of welding process. The spacing between solder joints is too small, which is not conducive to manual welding, and can only be solved by reducing work efficiency to improve welding quality. Otherwise, there will be danger left. Therefore, the determination of the minimum spacing between solder joints should take into account the nature and efficiency of the welding personnel.

Article source: PCB manufacturerhttp://www.yonghongpcb.com/