10.1 TUSB2077A Power Supply

V_CC should be implemented as a single power plane.

• The V_CC pins of the TUSB2077A supply 3.3-V power rail to the I/O of the TUSB2077A. 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 TUSB2077A power pins as possible with an optimal grouping of two of differing values per pin.

10.2 Downstream Port Power

• The downstream port power, VBUS, must be supplied by a source capable of supplying 5 V and up to 500 mA per port. Downstream port power switches can be controlled by the TUSB2077A signals. It is also possible to leave the downstream port power always enabled.
• A large bulk low-ESR capacitor of 22 μF or larger is required on each downstream port’s VBUS to limit in-rush current.
• The ferrite beads on the VBUS pins of the downstream USB port connections are recommended for both ESD and EMI reasons. A 0.1-μF capacitor on the USB connector side of the ferrite provides a low impedance path to ground for fast rise time ESD current that might have coupled onto the VBUS trace from the cable.