Is the serpentine wiring on the PCB more advanced?

Serpentine is a common wiring method used in PCB layout. Its main purpose is to adjust the delay and meet the system timing design requirements. However, serpentine lines can destroy signal quality and should be avoided when wiring. Although serpentine lines can degrade signal quality, in actual PCB designs, it is often necessary to intentionally wind the wires in order to ensure that the signals have sufficient hold time, or to reduce the time offset between the same set of signals. Moreover, the serpentine line is not "nothing".

Serpentine line

1. The main function of the serpentine trajectory is to compensate for the small delays in the "same set of related" signal lines, which are usually not processed by additional logic or less than other signals. The most typical is the clock line, which usually does not need to be processed by any other logic, so its delay will be less than other related signals.

2, the filtering effect, in the RF circuit, the serpentine trace can form an LC circuit, which has a filtering effect on a signal of a certain frequency.

3, the receiving antenna, we can see this effect on some mobile phones or radios. Some antennas are made using PCB traces.

4. Serpentine traces have different functions in different applications. If serpentine traces appear on the computer board, they are primarily used as filter inductors to improve the circuit's immunity to interference. The serpentine tracks on the computer motherboard are mainly used for some clock signals, such as PCIClk, AGPClk, which have two functions: a, impedance matching; b, filter inductor.

5. Short, narrow serpentine traces can be used as fuses.

Some suggestions for dealing with serpentine traces:

Try to increase the distance S of parallel segments, at least 4H or more. H refers to the distance of the signal to the reference plane.

Try to minimize the coupling length Lp. The delay of Lp is less than or equal to 6Tr.

Try to avoid snake lines if you can avoid snake lines.

If possible, serpentine traces of any angle can effectively reduce the coupling between each other.

The snake has a signal transmission delay caused by the serpentine line of the stripline being smaller than the microstrip trace.

High-speed high-speed and signal lines have strict timing requirements, so try not to take a serpentine line.