Front End Module Control - LG KF600d Service Manual

3. TECHNICAL BRIEF

3.25. Front End Module control

Implemented in the S-Gold3 (FL401) are three 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.
Table 12 FEM Control Logic
MODE Tx 1GHz
VDD ON
VC1 ON
VC2 OFF
VC1
PIN 14
GSM850_EGSM TX H
DCS_PCS TX L
GSM850 RX
L
EGSM900 RX L
DCS1800 RX L
PCS1900 RX L
C406
NA
C407
NA
LGE Internal Use Only
Tx 2GHz Rx GSM
ON
OFF
ON
VC2
PIN 13
L
H
L
L
L
L
C404
22p
G2
ANT RF
G1
SW401 C405
RF-800 100nH
ANT
11
Figure 40 FEM schematic
- 64 -
Rx EGSM
ON ON
OFF OFF
OFF OFF
R401
100ohm
R402
100ohm
C401 C402
100p 100p
Copyright © 2007 LG Electronics. Inc. All right reserved.
Rx DCS TX PCS
ON ON
OFF OFF
OFF OFF
2V85_VRF
Y2 A2 FE1
VCC GND
Y1 A1 FE2
NC7WV16P6X U401
C403
1000p
R408
DNI
Only for training and service purposes