TUSB2046B, TUSB2046BI

4PORT HUB FOR THE UNIVERSAL SERIAL BUS

WITH OPTIONAL SERIAL EEPROM INTERFACE

SLLS413B − FEBRUARY 2000 − REVISED DECEMBER 2004

14

POST OFFICE BOX 655303

APPLICATION INFORMATION

bus-powered hub, ganged-port power management (continued)

† TPS2041 and SN75240 are Texas Instruments devices.

‡ 120 µF per hub is the minimum required per the USB specification, version 1.1. However, TI recommends a 100-µF, low ESR, tantalum capacitor

per port for immunity to voltage droop.

§ LDO is a 5-V-to-3.3-V voltage regulator

DP1

DM1

DP2

DM2

DP3

DM3

DP4

PWRON1

PWRON2

PWRON3

PWRON4

OVRCUR1

OVRCUR2

OVRCUR3

OVRCUR4

DM4

DP0

DM0

VCC

XTAL1

XTAL2

EXTMEM

RESET

SN75240†

EN

IN

OC

OUT

D +

D −

5 V

GND

D +

D −

5 V

D +

D −

5 V

D +

D −

5 V

Downstream

Ports

TUSB2046B

TPS2041†

A

B

C

D

100

SN75240†

A

B

C

D

GND

GND

GND

1

µF

100

100

100

5 V

3.3 V

GND

D +

D −

Upstream

Port

SN75240†

A

B

5 V

GND

C

D

4.7

µF

0.1

µF

4.7

µF

GND

Ferrite Beads

Ferrite Beads

Ferrite Beads

Ferrite Beads

EEDATA/GANGED

6-MHz Clock

Signal

BUSPWR

3.3 V

System

Power-On Reset

OUT

OUT

IN

3.3 V

3.3 V

1.5 k

Ω

15 k

Ω

15 k

Ω

15 k

Ω

15 k

Ω

15 k

Ω

15 k

Ω

15 k

Ω

15 k

Ω

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

¶

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