USB3320C-EZK-TR Standard Microsystems (SMSC), USB3320C-EZK-TR Datasheet - Page 38

• Manufacturer Part Number: USB3320C-EZK-TR
• Manufacturer: Standard Microsystems (SMSC)

Specifications of USB3320C-EZK-TR

• Number Of Transceivers: 1
• Esd Protection: YeskV
• Operating Supply Voltage (typ): Not RequiredV
• Operating Temperature Classification: Industrial
• Operating Supply Voltage (max): Not RequiredV
• Operating Supply Voltage (min): Not RequiredV
• Pin Count: 32
• Mounting: Surface Mount
• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Lead Free Status / RoHS Status: Compliant

Revision 1.0 (07-14-09)
5.6.2.4
5.6.2.5
5.6.2.6
VBUS Pulsing with Pull-up and Pull-down Resistors
In addition to the internal VBUS comparators, the USB3320 also includes the integrated VBUS pull-up
and pull-down resistors used for VBUS Pulsing during OTG Session Request Protocol. To discharge
the VBUS voltage so that a Session Request can begin, the USB3320 provides a pull-down resistor
from VBUS to Ground. This resistor is controlled by the DischargeVbus bit 3 of the
register. The pull-up resistor is connected between VBUS and VDD33. This resistor is used to pull
VBUS above 2.1 volts so that the A-Device knows that a USB session has been requested. The state
of the pull-up resistor is controlled by the bit 4 ChargeVbus of the
and Pull-Down resistor values are detailed in
The internal VBUS Pull-up and Pull-down resistors are designed to include the R
in series. This external resistor is used by the VBUS Overvoltage protection described below.
VBUS Input Impedance
The OTG Supplement requires an A-Device that supports Session Request Protocol to have a VBUS
input impedance less than 100kΩ and greater the 40kΩ to ground. The USB3320 provides a 75kΩ
resistance to ground, R
VBUS Overvoltage Protection
The USB3320 provides an integrated overvoltage protection circuit to protect the VBUS pin from
excessive voltages that may be present at the USB connector. The overvoltage protection circuit works
with an external resistor (R
VBUS pin.
When voltage at the VBUS pin exceeds 5.5V, the Overvoltage Protection block will sink current to
ground until VBUS is below 5.5V. The current drops the excess voltage across R
USB3320 VBUS pin. The required R
as shown in
The Overvoltage Protection circuit is designed to protect the USB3320 from continuous voltages up to
30V on the R
The R
power can be found using the equation below:
VBUS
UseExternalVbusIndicator = 1
resistor must be sized to handle the power dissipated across the resistor. The resistor
OPERATING MODE
Table
VBUS
OTG Capable
Device only
Where:
5.7.
resistor.
Host
Table 5.7 Required R
Vprotect is the VBUS protection required
R
P
VB
RVBUS
VBUS
. The R
P
VBUS
RVBUS
is the resistor value, 1kΩ or 10kΩ.
is the required power rating of R
) by drawing current across the resistor to reduce the voltage at the
VB
DATASHEET
=
resistor tolerance is detailed in
VBUS
(
------------------------------------------- -
Vprotect 5.0
value is dependent on the operating mode of the USB3320
38
VBUS
R
Table
VBUS
Resistor Value
–
4.7.
)
2
Highly Integrated Full Featured Hi-Speed USB 2.0 ULPI Transceiver
VBUS
OTG Control
Table
4.7.
10kΩ ±5%
10kΩ ±5%
1kΩ ±5%
R
VBUS
VBUS
VBUS
register. The Pull-Up
and protects the
external resistor
SMSC USB3320
OTG Control
Datasheet