Datasheet
6-MHz Clock
Signal
BUSPWR
DP1
DM1
DP2
DM2
DP6
DM6
DP7
PWRON1
PWRON2
PWRON6
PWRON7
OVRCUR1
OVRCUR2
DM7
DP0
DM0
V
CC
GND
XTAL1
XTAL2
EXTMEM
RESET
5 V
3.3 V
GND
D +
D -
Upstream
Port
3.3 V LDO
§
SN75240
†
EN1
OC1
D +
D -
5 V
GND
D +
D -
5 V
D +
D -
5 V
D +
D -
5 V
Downstream
Ports
5-V Board Power
Supply
TUSB2077A
TPS2044
†
A
B
C
D
100 mF
‡
SN75240
†
A
B
C
D
GND
GND
GND
100 mF
‡
100 mF
‡
100 mF
‡
SN75240
†
A
B
5 V
GND
C
D
4.7 mF
0.1 mF
4.7 mF
EN2
EN3
EN4
OC2
OC3
OC4
OUT4
OUT3
OUT2
OUT1
EEDATA/GANGED
System
Power-On Reset
IN1
0.1 mF
IN2
15 kΩ
15 kΩ
15 kΩ
15 kΩ
1.5 kΩ
3.3 V
15 kΩ
15 kΩ
15 kΩ
15 kΩ
3.3 V
OVRCUR6
OVRCUR7
MODE
DP0PUR
¶
NOTES:
LDO is a 5-V-to-3.3-V voltage regulator. TPS76333 from Texas Instruments can be used.
All USB DP, DM signal pairs require series resistors of approximately 27
†
¶
TPS2042 and SN75240 are Texas Instruments devices. Two TPS2042 devices can be substituted for the TPS2044.
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
www.ti.com
SLLS414E –MARCH 2000–REVISED SEPTEMBER 2013
Self-Powered Hub, Individual-Port Power Management
In a self-powered configuration, the TUSB2077A can be implemented for individual-port power management
when used with two 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 10. TUSB2077A Self-Powered Hub, Individual-Port Power-Management Application
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