Ω

Ω

1.5 kΩ

Ω

Ω

Ω

Ω

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

TPS2044, TPS2042, and SN75240 are Texas Instruments devices. Two TPS2042 devices can be substituted for the TPS2044.

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.

SN75240

A

TPS2044

A

SN75240

A

3.3 V LDO

C

D

100 µF

B

100 µF

B

100 µF

B

100 µF

B

SN75240

A

16

TUSB2046B, TUSB2046I

SLLS413L – FEBRUARY 2000 – REVISED JUNE 2017

www.ti.com

Product Folder Links: TUSB2046B TUSB2046I

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Copyright © 2000–2017, Texas Instruments Incorporated

Typical Application (continued)

9.2.1 Design Requirements

For this design example, use the parameters listed in Table 2.

Table 2. Design Parameters

DESIGN PARAMETERS

VALUE

VCC Supply

3.3-V

Downstream Ports

4

Power Management

Individual-Port

Clock Source

6-MHz Crystal

External EEPROM

No

Power Source Mode

Self-Powered

9.2.2 Detailed Design Procedure

In a self-powered configuration, the TUSB2046x can be implemented for individual-port power management

when used with the TPS2044 because it is capable of supplying 500 mA of current to each downstream port and

can provide current limiting on a per-port basis. When the hub detects a fault on a downstream port, power is

removed from only the port with the fault and the remaining ports continue to operate normally. Self-powered

hubs are required to implement overcurrent protection and report overcurrent conditions. The SN75240 transient

suppressors reduce inrush current and voltage spikes on the data lines.

Figure 11. TUSB2046x Self-Powered Hub, Individual-Port Power-Management Application