If the input signal trace of a CMOS logic IC is in the vicinity of an output signal trace of another IC, crosstalk noise might be generated. Check if another trace is in the vicinity of the input signal trace or runs adjacently in parallel.
Generally, the following countermeasures can be considered:
- Adding a guard trace such as a GND trace between signal and adjacent traces.
- Reducing the length of the trace that runs in parallel with a signal trace.
For a description of crosstalk, please refer to “Precaution when Designing Circuits: Logic ICs”.