Datasheet

USB251xB/xBi
DS00001692C-page 6  2010 - 2015 Microchip Technology Inc.
2.0 BLOCK DIAGRAM
FIGURE 2-1: USB251XB/XBI HUB FAMILY BLOCK DIAGRAM
3.3 V
Upstream
PHY
Repeater
Controller
SCK
SDA
PHY#1
3.3 V
PLL
VDDA
VDDCR
Serial
interface
engine
Serial
interface
Port
controller
Port
power
USB data
downstream
Port
power
OC
sense
switch/
LED
drivers
USB data
downstream
Routing and port re-ordering logic
1.2 V reg
Bus-
power
detect/
V
bus
pulse
1.2 V reg
24 MHz
crystal
Upstream
USB data
To upstream
V
BUS
To I
2
C EEPROM or
SMBus master
PHY#x
Port #x
OC sense
switch driver/
LED drivers
TT
#x
TT
#1
...
Port #1
OC sense
switch driver/
LED drivers
OC
sense
switch/
LED
drivers
...
x indicates the number of available downstream ports: 2, 3, or 4