9.1 Digital Supplies 1.1-V and 3.3-V

The TUSB9261 requires a 1.1-V and 3.3-V digital power source.

The 1.1-V terminals are named VDD11. These terminals supply power to the digital core. The 1.1-V core allows for a significant reduction in both power consumption and logic switching noise.

The 3.3-V terminals are named VDD33 and supply power to most of the input and output cells. Both VDD11 and VDD33 supplies must have 0.1-μF bypass capacitors to VSS (ground) to ensure proper operation. One capacitor per power terminal is sufficient and should be placed as close to the terminal as possible to minimize trace length. TI also recommends smaller value capacitors like 0.01-μF on the digital supply terminals.

When placing and connecting all bypass capacitors, follow high-speed board design rules.

9.2 Analog Supplies 1.1-V and 3.3-V

TI recommends a Pi filter on all analog power terminals to minimize circuit noise. These filters can be combined on a per-rail basis for a total of two (VDDA11 / VDDA11_USB2) + (VDDA33).

Analog power terminals must have a 1-μF and a 10-μF bypass capacitor connected to VSSA (ground) to ensure proper operation. Place the capacitor as close as possible to the associated terminal to minimize trace length. TI also recommends smaller value capacitors such as 0.1-μF and 0.01-μF on the analog supply terminals.