USB4640-HZH-03 SMSC, USB4640-HZH-03 Datasheet - Page 22

• Manufacturer Part Number: USB4640-HZH-03
• Description: IC HSIC USB / FLASH CTRLR 48QFN
• Manufacturer: SMSC

Specifications of USB4640-HZH-03

• Design Resources: USB4640 Schematic
• Controller Type: HSIC USB 2.0 Hub, Flash Media
• Interface: I²C, Serial, SPI, USB
• Voltage - Supply: 3.3V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 48-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Other names: 638-1113

Revision 1.0 (06-09-09)
6.3
Port Power control using a USB Power Switch
The USB4640/USB4640i has a single port power control and over-current sense signal for each
downstream port. When disabling port power, the driver will actively drive a '0'. To avoid unnecessary
power dissipation, the internal pull-up resistor will be disabled at that time. When port power is enabled,
the output driver is disabled, and the pull-up resistor is enabled creating an open drain output.
If there is an over-current situation, the USB Power Switch will assert the open drain OCS signal. The
Schmitt trigger input will detect this event as a low. The open drain output does not interfere. The
internal over-current sense filter handles the transient conditions, such as low voltage, while the device
is powering up.
Port Power Control
Figure 6.1 Port Power Control with USB Power Switch
USB4640/40i
DATASHEET
High Speed Inter-Chip (HSIC) USB 2.0 Hub and Flash Media Controller
22
PRTCTL3
PRTCTL2
EN
EN
OCS
OCS
USB Power
USB Power
Switch
Switch
Device
Device
USB
USB
5 V
5 V
SMSC USB4640/USB4640i
Datasheet