How to suppress noise in a PAC (Power Controller Area Control) multi-core processor?

The multi-core processor of the intelligent controller PAC generates wideband switching noise during high-speed operation, mainly coupled to the system through power pins and clock network.

The suppression strategy employs a three-stage filtering: First, a π-type filter is formed at the processor core power input using a PWRA6045 series power inductor (6.8μH) and a low-ESR ceramic capacitor, which can filter out noise below 100MHz. Second, a PBZ1608A-102Z0T ferrite bead (1000Ω@100MHz) is deployed near each power pin for high-frequency decoupling, attenuating noise by more than 20dB. Simultaneously, a CMZ2012A-900T common-mode inductor (90μH) is connected in series with the processor clock line, and an ESDLC3V3D3B electrostatic discharge protection device is used to prevent noise leakage through the interface.

The layout ensures tight coupling between the power and ground planes, with a spacing of less than 0.2mm, and a complete ground plane is placed below the processor to minimize the radiation loop area. Testing shows that this solution keeps processor noise below EN55032 Class in the 30MHz-1GHz frequency band. The B limit is above 10dB, meeting the EMC requirements for industrial environments.