Fm Radio With Rds Function - LG KE600 - Cell Phone Service Manual

3.15 FM radio with RDS function

The FM receiver uses a digital low-IF architecture which allows for the elimination of external
components and factory adjustments. The receive (RX) section integrates a low noise amplifier (LNA)
supporting the worldwide FM broadcast band (87.5 to 108 MHz). An automatic gain control (AGC)
circuit controls the gain of the LNA to optimize sensitivity and rejection of strong interferers.
2V72_IO
U305
VCC
A
CLK32K
GND
C338
0.1u
2V72_IO
R336
10K
FM_RESETn
SCL
SDA
R337 0
Y
MC74VHC1GT50DFT2
-> MC74VHC1GT50DF1G
Figure 27 FM Radio circuit
C326
24p
1 18
GND1 VA
2 17
FMIP GND5
3 16
RF_GND U303 LOUT
4 15
FMIN SI4701 ROUT
5 14
GND2 GND4
6 13
GND3 VD
2V72_IO
C337
220n
- 53 -
3. TECHNICAL BRIEF
D308
C368
L303
PG05DBTFC
100nH NA
2V85_IO2 VBAT
FM_L
FM_R
C335 C336
4.7u 22n