Front End Module Control - LG GD310 Service Manual

3.22. 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.
Table12. 9 FEM Control Logic
MODE Tx 1GHz
VDD
VC1
VC2
VC1 (FE1) VC2 (FE2)
GSM850 / 900_TX H
GSM 1800 / 1900_ TX L
GSM850 / 900_RX H
GSM 1800 / 1900_ RX L
SW401
G2 ANT
G1
UFL-R-SMT10
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Tx 2GHz
ON
ON
ON OFF
ON ON
H
H
L
L
C416
1n
SW400
C420
G2
ANT RF
G1 11
100P
RF-800
L406
C437 100NH
DNI
Figure 32. FEM schematic
Rx 1GHz Rx 2GHz
ON ON
ON OFF
OFF OFF
2V85_VRF
LMSP43QA-538(CMOS)
NC2
24
NC1
FL400 23
LMSP43QA-538
ANT
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3. Technical Brief
R400 100R
R405 100R
C413 C412
100P 100P
LGE Internal Use Only
FE1
FE2