How to suppress common-mode interference on an industrial servo CAN bus?

Suppressing common-mode interference on the servo CAN bus is crucial for ensuring stable communication. Audiotech's suppression solutions include:

1) Using a common-mode choke, such as CML4532A-510T (51μH), at the front end of the CAN transceiver. Its impedance should be sufficiently high at both the CAN communication frequency (up to 1MHz) and the interference frequency (e.g., 30MHz).

2) Connecting a low-capacitance TVS array, such as ESDCANFD24VAPB (designed specifically for CAN FD), in parallel between CANH and CANL and ground, providing ESD and transient protection.

3) Using shielded twisted-pair cable (characteristic impedance 120Ω), with the shield grounded at both ends via capacitors (e.g., 1nF/Y1) to avoid low-frequency loops while providing high-frequency ground.

4) Ensuring 120Ω terminating resistors at both ends of the bus (typically at the driver and end nodes).

These measures can suppress common-mode noise applied to the CAN bus up to ±30V to within the transceiver's tolerance range (typically ±12V), ensuring error-free frames even in highly interfering industrial environments.