MIC2505/2506
Micrel
Applications Information
USB Application
Figure 4 depicts a low cost and robust implementation of a
four-port, self-powered USB hub circuit employing ganged
overcurrent protection.
Ferrite
Bead
(+)
4.45V to 5.25V
3.5A max.
(–)
100k
VBUS
D+
33µF
MIC5203-3.3
MIC5207-3.3
Downstream
LDO Regulator
3.3V USB Controller
V+
MIC2505-2/-1
USB
Port 1
0.01µF
D–
VBUS
33µF
33µF
33µF
IN
OUT
GND
ON/OFF
OVERCURRENT
EN
OUT
IN
GND
500mA max.
D+
1.0
µF
FLG
GND
GATE
D–
OUT
IN
VBUS
D+
GND
4.7
µF
Downstream
USB
Port 2
500mA max.
0.1µF
0.01µF
0.01µF
0.01µF
D+
D–
D–
GND
GND
Bold lines indicate
0.1" wide, 1-oz. copper
high-current traces.
VBUS
D+
Downstream
USB
Port 3
500mA max.
D–
GND
VBUS
D+
Downstream
USB
Port 4
500mA max.
D–
33µF
GND
Data
Figure 4. Ganged-Switch Self-Powered Hub
MIC2505/2506
10
April 1998
MICREL [ MICREL SEMICONDUCTOR ]
