Datasheet
DP1
DM1
DP2
DM2
DP3
DM3
DP4
PWRON1
PWRON2
PWRON3
PWRON4
OVRCUR1
OVRCUR2
OVRCUR3
OVRCUR4
DM4
DP0
DM0
V
CC
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
TUSB2077A
TPS2041
†
A
B
C
D
100 mF
‡
SN75240
†
A
B
C
D
GND
GND
GND
1 mF
100 mF
‡
100 mF
‡
100 mF
‡
5 V
3.3 V
GND
D +
D -
Upstream
Port
3.3 V LDO
§
SN75240
†
A
B
5 V
GND
C
D
4.7 mF
0.1 mF
4.7 mF
GND
Ferrite Beads
Ferrite Beads
Ferrite Beads
Ferrite Beads
EEDATA/GANGED
6-MHz Clock
Signal
BUSPWR
System
Power-On Reset
OUT
OUT
IN
3.3 V
1.5 kΩ
15 kΩ
15 kΩ
15 kΩ
15 kΩ
15 kΩ
15 kΩ
15 kΩ
15 kΩ
DP5 - DP7
DM5 - DM7
PWRON5 -7
OVRCUR5 -7
NC
3.3 V
MODE
DP0PUR
¶
NOTES:
LDO is a 5-V-to-3.3-V voltage regulator
All USB DP, DM signal pairs require series resistors of approximately 27
†
¶
TPS2041 and SN75240 are Texas Instruments devices.
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.
‡
§
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.
TUSB2077A
SLLS414E –MARCH 2000–REVISED SEPTEMBER 2013
www.ti.com
Bus-Powered Hub, Ganged-Port Power Management
When used in bus-powered mode, the TUSB2077A 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 9. TUSB2077A Bus-Powered Hub, Ganged-Port Power-Management Application
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