Hi-Speed USB Transceiver with 1.8V-3.3V ULPI Interface - 24MHz Reference Clock

SMSC USB3315

3

Revision 1.3 (11-02-07)

PRODUCT PREVIEW

General Description

The USB3315 is a highly integrated Hi-Speed USB2.0 Transceiver (PHY) that supports systems

architectures based on a 24MHz reference clock. It is designed to be used in both commercial and

industrial temperature applications.

The USB3315 meets all of the electrical requirements to be used as a Hi-Speed USB Host, Device,

or an On-the-Go (OTG) device. In addition to the supporting USB signaling the USB3315 also provides

USB UART mode

USB3315 uses the industry standard UTMI+ Low Pin Interface (ULPI) to connect the USB PHY to the

Link. The industry standard ULPI interface uses a method of in-band signaling and status byte transfers

between the Link and PHY, to facilitate a USB session. By using in-band signaling and status byte

transfers the ULPI interface requires only 12 pins.

The USB3315 uses SMSC’s “wrapper-less” technology to implement the ULPI interface. This “wrapper-

less” technology allows the PHY to achieve a low latency transmit and receive time. SMSC’s low

latency transceiver allows an existing UTMI Link to be reused by adding a UTMI to ULPI bridge. By

adding a bridge to the ASIC the existing and proven UTMI Link IP can be reused.

Figure 1 USB3315 Block Diagram

The USB3315 is designed to run with a 24MHz reference clock. By using a reference clock from the

Link the USB3315 is able to remove the cost of a crystal reference from the design.

The USB3315 includes a integrated 3.3V LDO regulator to generate its own supply from power applied

at the VBAT pin. The voltage on the VBAT pin can range from 3.1 to 5.5V. The regulator dropout

voltage is less than 100mV which allows the PHY to continue USB signaling when the voltage on

VBAT drops to 3.1V. The USB transceiver will continue to operate at lower voltages, although some

parameters may be outside the limits of the USB specifications. If the user would like to provide a 3.3V

supply to the USB3315, the VBAT and VDD3.3 pins should be connected together.

The USB3315 also includes integrated pull-up resistors that can be used for detecting the attachment

of a USB Charger. By sensing the attachment to a USB Charger, a product using the USB3315 can

charge its battery at more than the 500mA allowed when charging from a USB Host.

OTG

Carkit

Hi-Speed

USB

Transceiver

ULPI Interface

ULPI

Registers

and State

Machine

BIAS

Low Jitter

Integrated

PLL

Integrated

Power

Management

VBUS

ID

DP

DM

RBIAS

RESETB

VDD18

VDD33

REFCLK

VBAT

VDDIO

DIR

NXT

STP

CLKOUT

DATA[7:0]

CPEN