The 3.3V power system on AM26x ZCZ devices are explored using the AM263x controlCARD EVM (TMDSCNCD263), from the 3.3V buck-converter (TPS62913RPUR, U30) through the board power planes and ending in at the BGA bulk and per pin decoupling capacitor array. A common buck-converter supplies power for all of the AM263x digital I/O, analog I/O and the rest of the controlCard 3.3V loads. This is common in most designs where all 3.3V digital level I/O share a common power supply. Additional filtering for the local AM263x 3.3V analog power net is done through the LC filter of ferrite-bead FL13 and associated capacitors. This is used to create a low-IR drop low-pass filter that attenuates the higher frequency switching harmonics of the TPS62913RPUR regulator.

• Wide 15 mil traces need to be used for all power and ground return via fan-out.
• 3.3V I/O power tends to be shared across multiple devices in the system, recommend routing with very wide power planes across the PCB to minimize IR drops to all components including AM263x, AM263Px, or AM261x.
• A tightly coupled, adjacent ground return reference plane needs to be used for best transient performance and EMI coupling.
• A wide power plane entry that covers the BGA 3.3V power pin areas needs to be used for minimal IR drop and best transient performance.
• Larger packaged, lower-frequency, bulk capacitance needs to be placed adjacent to MCU BGA with vias directly to power plane paths.
• Smaller packaged, higher-frequency decoupling capacitance needs to be placed directly on BGA fan-out vias with as small of a dog-bone to power and ground return vias as possible.