LG -P350 Service Manual page 48

3. TECHNICAL BRIEF
3.12.2.3. HS-USB
The High-Speed USB module contains an embedded UTMI+ core with a built-in transceiver eliminating the
need for an external PHY. The HS-USB port is a standard 4-pin interface that connects directly to the USB
connector (USBPHY_DP, USBPHY_DN, USBPHY_ID and USBPHY_VBUS).
Two additional pins are required for PHY operations which include an external reference resistor pin
(USBPHY_REXT) and a USB system clock pin which the USB PHY uses to lock its internal PLL (SYS_CLK)
Figure. HS-USB connections and architecture
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