Only For Training And Service Purposes - LG TU550 Service Manual

3. TECHNICAL BRIEF
Figure. Schematic of USB block(MSM6275 Side & PM6650 Side)
TU550 have a protective circuit for booting from USB. When the phone is booting from USB_VBUS
without Battery, booting current is insufficient. Sometimes that can break the USB port of a computer.
For this reason, TU550 do not support booting from USB.
LGE Internal Use Only
Figure. Schematic of USB protective circuit
- 50 -
USB_OE_N
USB_VBUS
USB_DAT
USB_D+
USB_SE0
USB_D-
2.2K R306
4.7u C324
smd_1608h_9_r
Copyright © 2007 LG Electronics. Inc. All right reserved.

Only for training and service purposes

USB_ID
12
VREG_5V
13
USB_OE_N
14
VSW_5V
15
USB_CTL_N
16
USB_VBUS
17
USB_DAT
18
USB_D_P
19
USB_SE0
20
USB_D_M
21
GP1_DRV_N(MPP7)