LG GT500 - Page 160

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Only for training and service purposes
LGE Internal Use Only
4. TROUBLE SHOOTING
4.21.5 Checking RF Tx Path
A. GSM Tx path Level
③


③′
GSM/EDGE
PA + Ant Sw.
ANT
VAPC
RADCLK RADDAT RADSTR
VBAT
2.75 V
VRAD
1.8 V
VIO
PA PA
GSM850/
900 Input
DCS/PCS
Input
ESD
2.75 V
VRAD
LNA LNA LNA LNA LNA
A
D
A
D
0
90
LPF
+
ChP PhD
÷
N.M
VCO
LPF ChP PhD
÷
N.M
+
0
90
+
DAC
DAC
XO
DAC
VCO VCO
LNA LNA
WCDMA LB
WCDMA HB WCDMA HB WCDMA HB
CLK
DATA
STROBE
Serial
Control
WTxQB WTxQA
WTxIB WTxIA
GSM/EDGE AM
DAC
RFCtrl1 RFCtrl2
RFCtrl1 RFCtrl2
GSM/ EDGE HB GSM/ EDGE LB
WCDMA LB WCDMA HB WCDMA HB GSM/EDGE LB GSM/EDGE LB GSM/EDGE HB GSM/EDGE HB
WRxIA WRxIB
WRxQB WRxQA
EDataA EDataB
EDataC
EDataStr
WCDMA/GSM/GPRS/EDGE TRX
MCLK
CLKREQ
MCLKSec
XO
XOn XOp
26MHz
X-tal
VBAT
VccWPA
VccWPA
Power
coupler
Power
coupler
VccWPA VccWPA
RF Pow det
Det
En
Bias
DET
En
Bias
DET
En
Bias
DET
En
UL: 1920 – 1980 MHz DL: 2110 – 2170 MHz UL: 1749.9 – 1784.9 MHz DL: 1844.9 – 1879.9 MHz UL: 830 – 840 MHz DL: 875 – 885 MHz
824 – 915 MHz 1710 – 1910 MHz 1930 – 1990 MHz 1805 – 1880 MHz 925 – 960 MHz 869 – 894 MHz
WDCDCREF
WPOW_DET_EN
FB
Switch
PWM/PFM
En
Control
Logic
RFCtrl1
③


③′
③


③′
③


③′
③


③′