LG CU405 Service Manual page 78

4.5.1 Checking Ant. SW Module
Refer to chapter 3.3
ANT100 SW100
L90
6.8p
VREG_RF_2.85V
ANTENNA SWITCH MODULE LOGIC
LMSP4LMA-573TEMP_Rev B Later
GSM900/GSM850 TX
DCS/PCS TX
GSM 850 RX
GSM900 RX
DCS RX
PCS RX
UMTS 850
UMTS 1900
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
TP3
Schematic of RF Tx level
C80 56p
G2
ANT RF
G1
KMS-507
TP1
15nH L106
C86 C87
0.1u 33p
1K R100
ANT_SEL0
1K R101
ANT_SEL1
1K R102
ANT_SEL2
1K R103
ANT_SEL3
ANT_SEL0 ANT_SEL1 ANT_SEL2 ANT_SEL3
HIGH HIGH LOW LOW
HIGH LOW LOW LOW
LOW LOW LOW LOW
LOW LOW HIGH LOW
LOW HIGH HIGH LOW
LOW HIGH LOW LOW
HIGH LOW HIGH LOW
HIGH
LOW HIGH HIGH
4. TROUBLE SHOOTING
TP1
TP2
TP2
14 1
VC1 GSM1800RX1
13 2
VC2 GSM1800RX2
12 3
VC3 GSM1900RX1
11 4
VC4 GSM1900RX2
5
GSM900RX1
10 6
VDD GSM900RX2
7
GSM850RX1
9 8
GND1 GSM850RX2
18
GND2
C88 56p
20 15
GND3 U100 UMTS1
21 16
GND4 UMTS2
23
GND5
24 22
GND6 GSM1800_1900TX
26 25
GND7 GSM850_900TX
27
GND8
28 17
GND9 NC
L111
56p
LMSP4LMA-573TEMP
TP3
C101
1.2p
4.7nH
L120
L121
NA
L122
15nH
14 1
DCS_PCS_OUT DCS_PCS_IN
2
GND5 BS
NA
3
L123 GND4 TX_EN
11 4
VCC U102 VBATT
TQM7M5003
5
GND3 GND1
6
GND2 VRAMP
8 7
GSM_OUT GSM_IN
- 79 -
L109
WCDMA_850
1.8nH
L112
WCDMA_1900
1.5nH
R108
82
GSM_PA_BAND
11.4dB
GSM_PA_EN
5
RFOUT
R114
GSM_PA_RAMP
2.2K
LGE Internal Use Only