Issue link: https://resources.pcb.cadence.com/i/1541046
23. Managing Split Planes and Power Islands Correctly Split planes (dividing ground or power planes into isolated regions) and power islands are sometimes needed for mixed-signal isolation, multiple voltage rails, or special EMC/PI requirements. But if poorly implemented, they can create return current detours, radiate EMI, destabilize analog references, or cause voltage drops. Many board failures trace back to unplanned or accidental plane splits. Understanding when and how to split planes is critical for signal integrity, power delivery, and reliable operation. When And Where To Apply Apply split plane and power island management any time you have mixed-signal, analog/digital, high/noise-sensitive, or multi- voltage systems. Plan this during schematic and stackup definition, and revisit after placement, before final routing and signoff. Splitting the ground planes helps mitigate clock intermodulation