Miniature Hi-Speed USB Transceiver with 1.8V ULPI Interface

Revision 0.3 (02-04-08)

4

SMSC USB332x

PRODUCT PREVIEW

The USB332x includes an integrated 3.3V LDO regulator that may optionally be used to generate 3.3V

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 USB332x, the VBAT and VDD33 pins should be connected together.

The USB332x 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 USB332x can

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

In USB UART mode, the USB332x DP and DM pins are redefined to enable pass-through of

asynchronous serial data. The USB332x can only enter UART mode when the user programs the part

into this mode.

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

DM pin to the SPK_L pin. The USB332x can be configured to enter USB audio mode. In addition,

these switches are on when the RESETB pin of the USB332x is asserted. The USB audio mode

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

connect Full Speed USB from another PHY onto the USB cable.