What problems should be paid attention to in the serpentine wiring of PCB circuit board?
In PCB wiring, the serpentine line is a special wiring method. The serpentine line is a type of wiring method often used in Layout. Its main purpose is to adjust the delay and meet the system timing design requirements; the two most critical parameters are the parallel coupling length (Lp) and the coupling distance (S) . So, what are the issues that should be paid attention to in the serpentine wiring of the PCB circuit board? 1. Try to increase the distance of parallel lines, at least greater than 3H, H refers to the distance from the signal trace to the reference plane. In layman's terms, it is to traverse the line around a big bend. As long as the distance is large enough, the mutual coupling effect can be almost completely avoided. 2. Reduce the coupling length. When the double coupling length delay approaches or exceeds the signal rise time, the resulting crosstalk will reach saturation. 3. The signal transmission delay caused by the serpentine line of the strip line or the buried microstrip line is less than that of the microstrip line. 4. For signal lines with high speed and strict timing requirements, try not to use serpentine lines. 5. Serpentine traces at any angle can often be used, which can effectively reduce mutual coupling. 6. In high-speed PCB design, the serpentine line has no so-called filtering or anti-interference ability, and can only reduce the signal quality, so it is only used for timing matching. 7. Seriously consider the following important questions: (1) Is the jumper used the least? Do jumper wires pass through components and accessories? (2) Are the letters visible after assembly? Are their size and model correct? (3) In order to prevent blistering, is there a window on the large area of u200bu200bcopper foil? (4) Are there tool positioning holes? The above are some of the problems that engineers should pay attention to in the serpentine layout of PCB circuit boards. How much do you have?