How to avoid ground loops in hybrid grounding of power FTUs?

Hybrid grounding combines high-frequency multi-point grounding and low-frequency single-point grounding, avoiding ground loops. Design: Digital circuits use multi-point grounding, with each IC ground pin directly connected to the ground plane; analog circuits use single-point star grounding. Both are connected via a PBZ1608E600Z0T ferrite bead. The chassis ground uses single-point grounding, connected to earth via a low-impedance path. Cable shielding is grounded at the FTU end, and the other end is grounded via a 100nF/2kV capacitor. An isolated ground plane is provided on the PCB for sensitive circuits. This hybrid grounding minimizes ground loop area, reduces common-mode current, and lowers ground loop interference by more than 30dB, meeting the IEC 61000-4-8 power frequency magnetic field immunity test requirements.