LG KE820 - Front End Module Control; Power Amplifier Module

3. TECHNICAL BRIEF
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3.25. Front End Module control
Implemented in the S-Gold2 (U102) are three outputs which are ANT_SW1, ANT_SW2 and ANT_SW3
for direct control of front end modules with three logic input pins to select RX and TX mode as well as
low and high band operation.
3.26. Power Amplifier Module
The RF3158 (U401) is a high-power, dual-mode amplifier (PA) with integrated power control. This PA
is designed to operate both in a saturated mode for GMSK signaling and in a linear mode for 8PSK
modulation. Featuring input and output terminals that are internally matched to 50 ohms, the PAM is
designed to be the final amplification stage in a dual-mode GSM/EDGE mobile transmit lineup
operating in the 824 MHz to 915 MHz (low) and 1710 MHz to 1910 MHz (high) bands.
100R405
R441 100
R408
0
NA
C412
100p
C452
R403 100
C414
0.1u
C437
C408
C453
100p
C454
100p
100p
C401
C410
NA
VCTRL1
22 21
VCTRL2
20
VCTRL3
3
VDD
VSUPPLY
2
GND1
25
GND10
GND11
26
4
GND2 GND3
5 7
GND4 GND5
9 10
GND6
11
GND7
GND8
23
GND9
24
GSM_RX+
19
PCS_RX+
13 12
PCS_RX- TX1G
6
TX2G
8
FL308 YGHF-S006A
ANT
1
DCS_RX+
15 14
DCS_RX- EGSM_RX+
17 16
EGSM_RX-
18
GMS_RX-
C
C402
100p 1
0
12
NC1
10
15
NC2
NC3
20
3
TX_EN
VBATT
4
5
VMODE
VRAMP
6
BAND_SEL
2
GND1
8
GND10
22 23
GND11
GND2
9 11
GND3
13
GND4
14
GND5 GND6
16 17
GND7
19
GND8
21
GND9
1
HB_RFINHB_RFOUT
18
7
LB_RFIN
LB_RFOUT
RF3158
U401
3.9nH
L407
C411
NA
L406
10nH
100p
C409
2V85_RF
ANT_SW3
ANT_SW2
ANT_SW1
MODE Tx 1GHz Tx 2GHz Rx GSM Rx EGSM Rx DCS TX PCS
VDD ON ON ON ON ON ON
VCTRL1 ON ON OFF OFF OFF OFF
VCTRL2 OFF ON ON ON OFF OFF
VCTRL3 OFF OFF ON OFF ON OFF
Figure 41 FEM schematic