USB3500-ABZJ Standard Microsystems (SMSC), USB3500-ABZJ Datasheet - Page 29

• Manufacturer Part Number: USB3500-ABZJ
• Manufacturer: Standard Microsystems (SMSC)

Specifications of USB3500-ABZJ

• Operating Temperature (min): 0C
• Operating Temperature Classification: Commercial
• Operating Temperature (max): 70C
• Package Type: QFN
• Rad Hardened: No
• Lead Free Status / Rohs Status: Compliant

Hi-Speed USB Host, Device or OTG PHY With UTMI+ Interface
Datasheet
SMSC USB3500
6.7.1
6.7.2
6.7.2.1
6.7.2.2
6.7.2.3
USB PLUG
A
B
ID Detection
The USB3500 provides an ID pin to determine the type of USB cable connected. When the Mini-A
Plug of a USB cable is inserted into the Mini-AB connector, the ID pin is shorted to ground. When the
Mini-B Plug is inserted into the Mini-AB connector, the ID pin is allowed to float.
The USB3500 provides an integrated pull-up resistor to pull the ID pin to VDD3.3 when a Mini-B plug
is inserted and the cable is floating. When a Mini-A plug is connected, the pull-up resistor will be
overpowered and the ID pin will be brought to ground. To save current when a Mini-A Plug is inserted,
the ID pull-up resistor can be disabled by clearing the IDPULLUP pin. To prevent the ID pin from
floating to a random value, a weak pull-up resistor is provided at all times. The circuits related to the
ID comparator are shown in
VBUS Control
The USB3500 includes all of the Vbus comparators required for OTG. The VbusVld, SessVld, and
SessEnd comparators are fully integrated into the USB3500. These comparators are used to ensure
the Vbus voltage is the correct value for proper USB operation.
The VbusVld comparator is used by the Link, when configured as an A device, to ensure that the Vbus
voltage on the cable is valid. The SessVld comparator is used by the Link when configured as either
an A or B device to indicate a session is requested or valid. Finally the SessEnd comparator is used
by the B-device to indicate a USB session has ended.
Also included in the VBUS Control block are the resistors used for VBUS pulsing in SRP. The resistors
used for VBUS pulsing include a pull-down to ground and a pull-up to VDD3.3.
SessEnd Comparator
The SessEnd comparator is designed to trip when Vbus is less than 0.5 volts. When Vbus goes below
0.5 volts, the session is considered to be ended and SessEnd will transition from 0 to 1. The SessEnd
comparator is disabled when the Suspendn = 0. When disabled, the SessEnd output is 0. The
SessEnd comparator trip points are detailed in
SessVld Comparator
The SessVld comparator is used when the PHY is configured as either an A or B device. When
configured as an A device, the SessVld is used to detect Session Request protocol (SRP). When
configured as a B device, SessVld is used to detect the presence of Vbus. The SessVld comparator
is not disabled with Suspendn and its output will always reflect the state of VBUS. The SessVld
comparator trip point is detailed in
Note: The OTG Supplement specifies a voltage range for A-Device Session Valid and B-Device
VbusVld Comparator
The final Vbus comparator is the VbusVld comparator. This comparator is only used when configured
as an A-device. In the OTG protocol the A-device is responsible to ensure that the VBUS voltage is
within a certain range. The VbusVld comparator is disabled when Suspendn = 0. When disabled the
VbusVld will read 0. The VbusVld comparator trip points are detailed in
Session Valid comparator. The USB3500 PHY combines the two comparators into one and
uses the narrower threshold range.
PERIPHERAL
OTG ROLE
Table 6.2 IdGnd vs. USB Cable Type
HOST
Figure 6.8
DATASHEET
Table
and their related parameters are shown in
5.7.
29
Table
ID VOLTAGE
5.7.
3.3
0
Table
5.7.
Revision 1.0 (06-05-08)
Table
I
D
G
0
1
ND
5.7.