VDD11 and VDDA11 should be implemented as a single power plane, as should VDD33, VDDA33 and VDDA33_OSC.
- The VDD11 terminals supply 1.1-V power to the core of the TUSB8040A1. This power rail can be isolated from all other power rails by a ferrite bead to reduce noise.
- The DC resistance of the ferrite bead on the 1.1-V power rail can affect the voltage provided to the device, due to the high current draw on the power rail. The output of the 1.1-V voltage regulator may need to be adjusted to account for this, or a ferrite bead with low DC resistance (less than 0.05 Ω) can be selected.
- The VDD33 terminals supply 3.3-V power to the I/O of the TUSB8040A1. This power rail can be isolated from all other power rails by a ferrite bead to reduce noise.
- All power rails require a 10-μF capacitor or 1-μF capacitors for stability and noise immunity. These bulk capacitors can be placed anywhere on the power rail. The smaller decoupling capacitors should be placed as close to the TUSB8040A1 power pins as possible, with an optimal grouping of two of differing values per pin.