EVB-USB3340 USB Transceiver Evaluation Board User Manual
Revision 1.1 (12-14-10)
2
SMSC USB3340 EVB
USER MANUAL
1 Introduction
This user manual is for the USB3340 USB Transceiver Evaluation Board (EVB) for use with USB3340
products with the integrated USB switch.
The USB3340 features a ULPI interface to support systems with USB Host, Device, or On-the-Go
(OTG) capability. The integrated switch can be used to multiplex a Full Speed USB signal or audio
signals over the HS USB DP/DM pins.
2 Overview
The USB3340 EVB is a Daughter Card designed to plug into a user's test system using a T&MT
connector. The card attaches to a USB link layer to create a USB Host, Device, or On-the-Go (OTG)
system. The board edge connector meets the UTMI+ Low Pin Interface (ULPI) Standard requirements
for the T&MT connector.
A link to the ULPI Working Group Page is available at www.smsc.com or may be obtained from your
local FAE. The USB3340 EVB includes USB3340 packaged silicon and all external components
required for the USB transceiver function.
This manual describes PCB assembly PCB-7220AZ.
2.1
Supplying VBUS Voltage
In Host or OTG operation, the USB3340 EVB must provide 5 Volts on V
BUS
at the USB connector. The
USB3340 EVB includes a switch that can drive V
BUS
using the 5 Volt supply that comes from pin 28
of the T&MT connector.
The VBUS switch is controlled by the CPEN signal from the USB3340. The USB controller dictates
the state of CPEN by programming the ULPI register in the USB3340. The 5 Volt switch is backdrive
protected when in the off state. The switch does not provide protection from reverse currents when it
is on. See
for more information on configuring the USB3340 EVB for
OTG and Host operation.
2.2
ULPI I/O Voltage
The USB3340 supports variable ULPI I/O voltage signaling. The ULPI I/O voltage is supplied in one
of two ways. By default, the EVB is shipped with VDDIO supplied by the on-board LDO.
Resistor R18 is used to set VDDIO, the digital logic high voltage. To change the value of VDDIO,
calculate a new value for R18 (ohms) as follows.
R18 = (VDDIO/1.225-1) x 169000
VDDIO must be in the range of 1.8 Volts - 3.3 Volts nominal.
VDDIO can also be supplied to the USB3340 from the T&MT connector instead of using the LDO. To
do this, the LDO (U10) must be removed.
The VDDIO voltage level that has been configured on the USB3340 EVB must be the same as the
ULPI I/O voltage level that the link is using.
