LG MG220 Service Manual page 16

FL500
Front End Module
GSM
850
EGSM
DCS
PCS
D
D
I
I
P
P
3.2.1. RF Front End
RF front end consists of Front End Module(FL500), quad band LNAs integrated in transceiver(U501).
The Received RF signals (GSM-850 869MHz ~ 894MHz, EGSM 880 MHz ~ 960MHz, DCS 1710 MHz
~ 1880 MHz, PCS 1930MHz ~ 1990MHz) are fed into the antenna or mobile switch. An antenna
matching circuit is between the antenna and the mobile switch. The Front End Module(FL500) is used
for control the Rx and TX paths. And the input signals ANT_SW1 and ANT_SW2 of a FL500 are
directly connected to baseband controller to switch either TX or RX path on. Front End Module(FL500)
is an antenna switch module for Quad band phone. The logic and current is given below Table 3-2.
GSM 850/EGSM RX
DCS/PCS RX
GSM-850/EGSM TX
DCS/PCS TX
LNA
GSM
850 PGA
ADC
ADC
EGSM
DCS
ADC
ADC
PCS
0 /
0 / VCO + FREQUENCY
VCO + FREQUENCY
90 SYNTHESIZER
90 SYNTHESIZER
Figure 1. RF Receiver Block
ANT_SW1(PIN 15)
ANT_SW1 2(PIN 14)
0 V
2.5~3.0 V
0 V 2.5~3.0 V
2.5~3.0 V 2.5~3.0 V
Table 3-2. The Logic and Current
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3. H/W Circuit Description
U501/Si4210
LOW
LOW
IF
IF
PGA
DAC
DAC
DAC
DAC
X500
VC-TCXO
26MHz
Current
0 V < 0.1 mA
0 V < 0.1 mA
< 0.1 mA
< 0.1 mA
I
Baseband
Baseband
(TI)
(TI)
U101
U101
Q
(Calypso +)
(Calypso +)
+
+
U100
U100
(IOTA)
(IOTA)