LG KC780 Service Manual page 105

5. TROUBLE SHOOTING
PGND GSM850_900_IN
15
GND3 TX_EN
8
GND2
11
GND1 VRAMP
14
U501
TQM7M5005
BY_CAP2 VBATT
9
BY_CAP1
13
GSM850_900_OUT MODE_SELECT
10
DCS_PCS_OUT DCS_PCS_IN
12
5.14.3 FEM Circuit
See the 1.2.1 FEM Circuit.
LGE Internal Use Only
TX_RAMP
VBAT
7
6
5
4
BS
3
2
1
C520 C506 C521 C522
22u
1000p 27p 100p
Fig 15 PAM circuit (U500)
PA_BAND
R509
1
R511
1
R512
1.2K
C507 C523 C524
L503
100p 100p 820p
NA
- 106 - Copyright © 2008 LG Electronics. Inc. All right reserved.
PA_MODE
R513 1
R516 R514 1
4.7nH
L504
DNI
Only for training and service purposes
TXLB
PA_EN
TX_RAMP
PA_BAND
PA_MODE
TXHB