LG KF690 Service Manual page 23

3. TECHNICAL BRIEF
3.4.6 FM Radio (U103 : SI4702-C19-GM)
The Si4702's patented digital low-IF architecture reduces external components and eliminates the
need for factory adjustments. The receive (RX) section integrates a low noise amplifier (LNA)
supporting the worldwide FM broadcast band (76 to 108 MHz). An automatic gain control (AGC) circuit
controls the gain of the LNA to optimize sensitivity and rejection of strong interferers.
FM_CONTROL
C154 100p
FM_ANT
FM_BUSEN
FM_I2C_SCL
FM_I2C_SDA
SLEEP_CLK
[Fig. 3.7] FM Radio system architecture in the KF690
LGE Internal Use Only
21 20 19 18 17 16
1
NC1 GND3
2
U103
FMIP LOUT
3
RFGND ROUT
SI4702-C19-GM
4
GND1 GND2
5
_RST
6 7 8 9 10
TP100
TP101
TP102
- 24 -
VREG_MSMP_2.7V
C152
C153
1u 10n
15
14
FM_AUDIO_L
13
FM_AUDIO_R
12
11
VD
VREG_MSMP_2.7V
C166
0.1u
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