TUSB2040A

4-PORT HUB FOR THE UNIVERSAL SERIAL BUS

WITH OPTIONAL SERIAL EEPROM INTERFACE

SLLS288B – JANUARY 1998 – REVISED MARCH 1998

13

POST OFFICE BOX 655303

APPLICATION INFORMATION

self-powered hub, ganged port power management

A self-powered TUSB2040A can also be implemented using ganged port power management (see Figure 11).

This implementation is similar to the individual power management except one TPS2015 provides power

switching and overcurrent protection for two ports. Although this is a more economical solution, a fault on one

downstream port causes power to be removed from both downstream ports.

48-MHz Clock

Signal‡

Figure 11. TUSB2040A Self-Powered Hub, Ganged Port Power Management

† TPS2015, TPS7133, and SN75240 are Texas Instruments devices.

‡ See Figures 7 and 8.

§ Minimum value required per USB specification, version 1.0.

DP1

DM1

DP2

DM2

PWRON1

PWRON2

PWRON3

PWRON4

OVRCUR1

OVRCUR2

OVRCUR3

OVRCUR4

GND

XTAL1

XTAL2

EXTMEM

RESET

TPS2015†

IN

EN

OUT

D +

D –

5 V

GND

D +

D –

5 V

Downstream

Ports

NC

NC

NC

OC

TUSB2040A

DP3

DM3

DP4

DM4

SN75240†

A

B

C

D

120

µF§

GND

120

µF§

DP0

DM0

VCC

5 V

3.3 V

GND

D +

D –

Upstream

Port

TPS7133†

SN75240†

A

B

5 V

GND

C

D

4.7

µF

0.1

µF

4.7

µF

Ferrite Beads

5 V Board Power

Supply

PG

Ferrite Beads

0.1

µF

TPS2015†

IN

EN

OUT

D +

D –

5 V

GND

D +

D –

5 V

OC

GND

120

µF§

Ferrite Beads

0.1

µF

SN75240†

A

B

C

D

120

µF§

BUSPWR/SCL

GANGED/SDA

3.3 V

Ferrite Beads