Hi-Speed USB Transceiver with 1.8V ULPI Interface - 26MHz Reference Clock

Revision 1.0 (05-08-07)

4

SMSC USB3311

PRODUCT PREVIEW

The USB3311 includes a integrated 3.3V LDO regulator to generate its own supply from the VBAT pin.

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 USB3311 the

VBAT and VDD3.3 pins should be connected together.

The USB3311 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 USB3311 can

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

The USB3311 also includes support for USB audio modes. The user can program the PHY into UART

or audio mode while in synchronous mode. The USB3311 can only enter these modes when the user

programs the part into these modes.

In USB UART mode, the USB3311 DP and DM outputs will be redefined to transmit on DM and to

receive on DP. In UART mode the USB3311 can function as a bi-directional transceiver.

In USB audio mode the DP pin is shorted to the SPKR_R/M pin with a switch. The DM pin is shorted

to the SPKR_L pin. The user can then initiate audio signaling over the USB cable. In addition to audio

signals, the switches can also be used to connect Full Speed USB from another PHY onto the USB

cable.