Automotive USB Transceiver with Variable Voltage ULPI and Selectable Reference Frequency

SMSC USB83340

3

Revision 1.1 (05-05-10)

PRODUCT PREVIEW

General Description

SMSC’s USB83340 is a Hi-Speed USB 2.0 transceiver that provides a configurable physical layer

(PHY) solution well suited for automotive applications.

The frequency of the reference clock is user selectable. The USB83340 includes an internal oscillator

that may be used with either a quartz crystal or a ceramic resonator. Alternatively, the crystal input can

be driven by an external clock oscillator. Another option is the use of a 60 MHz external clock when

using the ULPI Clock In mode.

Several advanced features make the USB83340 the transceiver of choice by reducing both eBOM part

count and printed circuit board (PCB) area. Outstanding ESD robustness eliminates the need for

external ESD protection devices in typical applications. The internal Over-Voltage Protection circuit

(OVP) protects the USB83340 from voltages up to 30 V on the VBUS pin. By using a reference clock

from the Link, the USB83340 removes the cost of a dedicated crystal reference from the design, and

the integrated USB switch enables unique product features with a single USB port of connection. The

USB83340 includes integrated 3.3 V and 1.8 V regulators, making it possible to operate the device

from a single power supply.

The USB83340 is optimized for use in applications where a low operating current and standby currents

are essential. The USB83340 operates from a single supply and includes integrated regulators for its

supplies. The USB83340 also supports the Link Power Management protocol (LPM) to further reduce

USB operating currents.

The USB83340 also includes integrated battery charger detection circuitry. These circuits are used to

detect the attachment of a USB charger. By sensing the attachment to a USB charger, a product using

the USB83340 can draw more than 500 mA from the USB connector.

The USB83340 meets all of the electrical requirements for a Hi-Speed USB host, device, or an On-

the-Go (OTG) transceiver. In addition to the supporting USB signaling, the USB83340 also provides

USB UART mode and USB audio mode.

USB83340 uses the industry standard UTMI+ Low Pin Interface (ULPI) to connect the USB PHY to

the Link. ULPI uses a method of in-band signaling and status byte transfers between the Link and PHY

to facilitate a USB session with only twelve pins.

The USB83340 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.

The USB83340 includes an integrated 3.3 V LDO regulator that may optionally be used to generate

3.3 V from power applied to the VBAT pin. The voltage on the VBAT pin can range from 4.5 to 5.5 V.

The VBAT and VDD33 pins should never be connected together.

In USB UART mode, the USB83340 DP and DM pins are redefined to enable pass-through of

asynchronous serial data. The USB83340 will enter UART mode when programmed.

In USB audio mode, a switch connects the DP pin to the SPK_R pin, and another switch connects the

DM pin to the SPK_L pin. The USB83340 can be configured to enter USB audio mode. In addition,

these switches are on when the RESETB pin of the USB83340 is asserted. The USB audio mode

enables audio signaling from a single USB port of connection, and the switches may also be used to

connect Full-Speed USB from another transceiver to the USB connector.