A source capable of supplying 5V and up to 500mA
per port must supply the downstream port power, VBUS. The TUSB2514B signals can control the downstream port
power switches. Leaving the downstream port power as always enabled is also
possible.
The VBUS of each downstream port requires a
large-bulk low-ESR capacitor of 22µF or larger to limit in-rush current.
TI recommends the ferrite beads on the VBUS pins
of the downstream USB port connections for both ESD and EMI reasons. A 0.1µF
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.