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3.7.2.3. Synthesizer
WCDMA Transmitter Synthesizer
All RF frequencies are generated in the WCDMA Tx 4 GHz VCO, subsequently divided by
2 or 4 to arrive at the final frequency.
The WCDMA Tx RF-VCO is locked to the XO in a fractional N PLL consisting of a prescaler, a phase frequency
detector, a charge-pump, a sigma-delta modulator, and a fully integrated loop filter.
Automatic trimming of the VCO center frequency and the RC constant ensures that the variation of the PLL
dynamics is sufficiently low.
GSM/EDGE and WCDMA Receiver Synthesizer
All RF frequencies are generated in either of the two 4 GHz VCOs, subsequently divided by 2 or 4 (depending
on final frequency). The selection of either of the two VCOs is done using the digital bus.
The selected RF-VCO is locked to the XO in a fractional N PLL consisting of a prescaler, a phase-frequency
detector, a charge-pump, a sigma-delta modulator, and a fully integrated loop filter.
Automatic trimming of the VCO center frequency and the RC constant ensures that the variation of the PLL
dynamics is sufficiently low.
VDDA_2V8
VRAD_2V8
U108
1
5
_OE
VCC
2
TX_ADC_STRB
A
3 GND
4
Y
SN74LVC1G125DRLR
TX_ADC_STRB_2V8
WRX_Q_N
WRX_Q_P
WRX_I_N
WRX_I_P
AMP_FREQ_LSB
DATA_STR
QDATA_AMP_MSB
IDATA_FREQ_MSB
RF_CTRL_STR_1
RF_CTRL_DATA
RF_CTRL_CLK
TESTOUT
MCLKREQ
MCLK
R144
0
TN4-26562
26MHz
2 GND1
HOT1
1
HOT2
GND2
3
4
X100
R157
0
MCLKSEC
VDIGRAD_1V8
WTX_I_P
WTX_I_N
WTX_Q_P
WTX_Q_N
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
R123
FB100
R124
390
closed to RF3300
VRAD_2V8
R129
27
R130
VDDA_2V8
R134
27
1
WRXQN
2
51
WRXQP
VCCA2
27
VCCA1
3
WRXIN
4
56
WRXIP
ETXHB
54
ETXLB
6
EDATAC
7
52
EDATASTR
EAMMOD
8
EDATAA
9
50
EDATAB
ERXHB2
48
ERXHB1
10
STR
46
ERXLB2
11
44
U111
DATA
ERXLB1
RF3300
12
42
CLK
WRXHB2
38
WRXHB1
13
TESTOUT
14
40
CLKREQ
WRXLB
15
MCLK
37
RFCTRL1
DNI
WDCDC_EN
17
36
XON
RFCTRL2
18
R145
XOP
20
35
MCLKSEC
WTXLB
21
VCCD
31
R151
WTXHB3
23
33
WTXLP
WTXHB2
24
29
0
WTXIN
WTXHB1
25
WTXQP
26
57
WTXQN
PGND
R161
0
RF TRANCEIVER
R165
0
Figure 3-7-4. WCDMA Transceiver schematic
- 65 -
3. TECHNICAL DESCRIPTION
560
1800
C159
3.9p
L104
3.3nH
C164
15p
0
L106
GTX_1800_1900
2.2nH
C172
3.3p
GTX_850_900
L110
L111
8.2nH
NA
C177
3.3p
GTX_VAM
L113
L114
10nH
NA
C178
33p
560
R143
TX_ADC_STRB_2V8
39nH L116
C180
DNI
FL105
SAFEB897MAM0F00
R152
0
1
4
IN
OUT
WTX_BAND_8_5_TO_PA
G1
G2 G3
2
3
5
FL106
SAFEB1G95KA0F00
3
G3
0
R162
1
4
IN
OUT
WTX_BAND_1_TO_PA
G1
G2
2
5
FL107
SAFEA1G88KB7F00
3
G3
0
R166
1
4
IN
OUT
WTX_BAND_2_TO_PA
G1
G2
2
5
4.3nH
R125
GRX_1900
FL103
L105
GND6
GND5
10
5
NA
GND4
GND3
8
3
GND2
GND1
7
2
OUT_1960
IN_1960
6
4
3.9nH
R128
OUT_1842_5
IN_1842_5
GRX_1800
9
1
SAWEN1G84BC0F25
L107
NA
0
R133
GRX_900
FL104
L109
GND6
GND5
10
5
NA
GND4
GND3
8
3
GND2
GND1
7
2
OUT_942_5
IN_942_5
6
4
0
R140
OUT_881_5
IN_881_5
GRX_850
9
1
SAWEN881MBA0F25
L112
NA
R142
18p
WRX_BAND_1
ADOUT
L115
C179
5.6nH
10nH
WRX_BAND_2
L117
2.2nH
TEMP SENSOR
L118
10nH
WRX_BAND_8_5
NA
L119
L120
1.8p
LGE Internal Use Only
RTEMP
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