How to reduce the crosstalk problem of high frequency PCB circuit wiring?
When it comes to high-frequency circuit wiring, PCB engineers are more troubled by the crosstalk of high-frequency signals.
Methods to reduce the crosstalk problem of high-frequency PCB circuit wiring
Because high-frequency signals are transmitted along the transmission line in the form of electromagnetic waves, the signal line will act as an antenna, and the energy of the electromagnetic field will be emitted around the transmission line. Undesired noise is generated between the signals due to the mutual coupling of electromagnetic fields. For crosstalk. In order to reduce the crosstalk of high-frequency signals, it is required to do as much as possible during PCB design and wiring:
1. When the wiring space permits, insert a ground wire or ground plane between the two wires with more serious crosstalk, which can play a role in isolation and reduce crosstalk.
2. When there is an electromagnetic field in the space around the signal line, if parallel distribution cannot be avoided, a large area of "ground" can be arranged on the opposite side of the parallel signal line to greatly reduce interference.
3. When the wiring space permits, increase the distance between adjacent signal lines, reduce the parallel length of the signal lines, and try to make the clock line perpendicular to the key signal line.
4. If parallel wiring in the same layer is almost unavoidable, the wiring directions must be perpendicular to each other in two adjacent layers.
5. In PCB design, it is advisable to surround the clock line with a ground wire and punch more ground wire holes to reduce distributed capacitance, thereby reducing crosstalk.
6. The high-frequency signal clock should try to use a low-voltage differential clock signal and the ground mode.
7. Do not suspend the unused input terminal, but ground it or connect it to the power supply, because the dangling wire may be equivalent to the transmitting antenna, and the grounding can inhibit the emission.
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