PCB design is a very broad technology involves a lot of factors that affect the design results . This article first put aside other factors , it is only about a few aspects of PCB design experience, for your reference :
1 have a reasonable trend : as input / output, AC / DC , strong / weak signal , high frequency / low frequency , high / low , etc. ... , they should be linearly toward (or separation ) , shall be mutually blend. Its purpose is to prevent mutual interference. The best to be a straight line , but generally not easy to achieve , is the most unfavorable toward the ring , but fortunately you can set the isolation brought about improvements. For DC , small signal , low voltage PCB design requirements can be lower . Therefore, the " reasonable" is relative.
2 Select a good grounding point : I wonder how many tiny ground engineering and technical personnel have done it much discussed , which shows its importance. Point to the requirements of the general case, such as: a plurality of front ground of the amplifier should be connected to the mains after confluence ... etc. . In reality, due to various constraints is difficult to completely done, but should try to follow . This problem is quite flexible in practice . Everyone has their own set of solutions. As for specific boards can be explained , it is easy to understand.
(3) reasonable layout power filtering / decoupling capacitors : general schematic drawing only certain power filtering / decoupling capacitors , but pointed out that they should be connected to each where . In fact, these capacitors for switching devices ( gates ) , or other applications that require filtering / decoupling components and settings are arranged on these capacitors should be as close to these component parts , too far away no role in the. Interestingly, when reasonable power filtering / decoupling capacitor arrangement , the ground of the problem does not seem so obvious.
4 lines with stress : Conditional wide line never done meticulous ; high-voltage and high-frequency line should park slide , not a sharp chamfered corner nor right angle . Grounding should be as wide, preferably using large area deposition of copper, which issues the docking location considerable improvement .
5 Although some problems occurred in post-production , but it is the PCB design brings, they are: too over the line hole , copper process slightest mistake will lay hidden. Therefore , the design should minimize the hole over the line . With parallel lines to the density is too big, it is easy to weld together into one . Therefore, the linear density should be considered to determine the level of the welding process . From the solder is too small, is not conducive to manual welding , work efficiency can be solved to reduce the weld quality . Otherwise it will stay hidden. Therefore, to determine the minimum distance should be considered solder joint quality and efficiency of welding personnel.
6 pads over the line or hole size is too small, or the pad size and drill size mismatch . The former unfavorable artificial drilling , CNC drilling latter disadvantage . The pad is easy to drill into the "c" shaped , heavy drilling off the pad. Wire is too thin , and a large area of the wiring area is not set and no copper , likely to cause corrosion uneven. That is, when corrosion is not finished wiring area , thin wire corrosion is likely overdone , or similar non- broken off, or completely off . Therefore, the role is not only set to increase copper ground area and interference . The reliability of the above factors are compromised on the quality of the board and future products.
