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3. TECHNICAL BRIEF
LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3.21 Front End Module control
Implemented in the S-Gold3 (FL400) are two outputs which are FE1, FE2 for direct control of front end
modules with two logic input pins to select RX and TX mode as well as low and high band operation.
FEM need 2V85_VRF supply.
MODE
Tx 1GHz
Tx 2GHz
Rx 1GHz
Rx 2GHz
VDD ON ON ON ON
VC1 ON OFF ON OFF
VC2 ON ON OFF OFF
VC1 (FE1)
GSM 1800 / 1900_ TX
L
L
L
H
H
VC2 (FE2)
GSM850 / 900_RX
GSM 1800 / 1900_ RX
H
H
LMSP43QA-538(CMOS)
L
GSM850 / 900_TX
C410
0.5p
100nH
L406
C407
DNI
6.8nH
L404
C411
0.5p
ANT
G1
G2
G3
ANT400
WFL-R-SMT10
2V85_VRF
C400
1000p
C406
100p
100ohm
R403
100ohm
R402
RF-800
SW400
ANT
G1
G2
RF
15
GSM1800_RX1
5
6
GSM1800_RX2
GSM1900_RX1
7
8
GSM1900_RX2
17
GSM850_900_TX
GSM850_RX1
1
2
GSM850_RX2
GSM900_RX1
3
4
GSM900_RX2
23
NC1
24
NC2
19
VC1
VC2
20
21
VDD
11
ANT
GND1
9
GND2
10
12
GND3
GND4
13
GND5
14
GND6
16
18
GND7
22
GND8
GSM1800_1900_TX
LMSP43QA-538
FL400
100p
C402
C401
100p
FE1
FE2
Figure 29 FEM schematic