EN

IN

OC

OUT

D +

D -

5 V

GND

D +

D -

5 V

D +

D -

5 V

D +

D -

5 V

Downstream

Ports

A

B

C

D

A

B

C

D

GND

GND

GND

1 µF

Ferrite Beads

Ferrite Beads

Ferrite Beads

Ferrite Beads

3.3 V

OUT

OUT

IN

15 kΩ

15 kΩ

15 kΩ

15 kΩ

1.5 kΩ

15 kΩ

15 kΩ

15 kΩ

15 kΩ

SN75240

A

D

SN75240

A

3.3 V LDO

A

100 µF

B

100 µF

B

100 µF

B

100 µF

B

SN75240

A

TPS2041

A

NOTES: A.

B.

C. LDO is a 5-V-to-3.3-V voltage regulator

D. All USB DP, DM signal pairs require series resistors of approximately 27

TPS2041 and SN75240 are Texas Instruments devices. The

outputs of the TPS204n are open drain. A 10-k

pullup is

recommended.

120 µF per hub is the minimum required per the USB specification. However, TI recommends a 100-µF, low ESR,

tantalum capacitor per port for immunity to voltage droop.

OCn

Ω

Ω to ensure proper termination. An optional filter

capacitor of about 22 pF is recommended for EMI suppression. This capacitor, if used, must be placed between the hub

terminal and the series resistor, as per section 7.1.6 of the USB specification.

TUSB2046B

TUSB2046BI

SLLS413I – FEBRUARY 2000 – REVISED SEPTEMBER 2013

www.ti.com

Bus-Powered Hub, Ganged-Port Power Management

When used in bus-powered mode, the TUSB2046B supports up to four downstream ports by controlling a

TPS2041 device which is capable of supplying 100 mA of current to each downstream port. Bus-powered hubs

must implement power switching to ensure current demand is held below 100 mA when the hub is hot-plugged

into the system. Utilizing the TPS2041 for ganged-port power management provides overcurrent protection for

the downstream ports. The SN75240 transient suppressors reduce inrush current and voltage spikes on the data

lines. The OVRCUR signals must be tied together for a ganged operation.

Figure 11. TUSB2046B Bus-Powered Hub, Ganged-Port Power-Management Application

14

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