2025-09-18 2:34 AM
Hi everybody,
I am kindly new to the EMI requirement field. I am currently designing a stepper motor control board based on a L6470 driver. I have strict EMI standards to meet so I am thinking about filtering the noise and perturbations caused by the switching in my bipolar stepper motor phase wires.
I am already aware of twisted wires and shielded cables, but I was thinking more of a passive filtering on my pcb between my driver's phase out pins and my board-motor cable connector.
I know there is a lot of filtering possibilities from CMC + low ceramic cap to ferrite beads and RC snubbers.
What would you recommend ?
Thank you in advance and best regards,
Paul.
2025-09-18 3:07 AM - edited 2025-09-18 3:19 AM
Ferrite beads are very effective, especially combined with a low value cap, effectively creating a kinda-sorta LC filter.
But achieving good EMI performance is more than just filtering; it requires attention to all aspects of the design. There's lots of good information to be found in this document:
EMC design guides for motor control applications