LG CU405 Service Manual page 68

VREG_RF_2.85V
C86
0.1u
ANT_SEL0
ANT_SEL1
ANT_SEL2
ANT_SEL3
CONTROL LOGIC
Mode
GSM850/900 Tx
GSM1800/GSM1900 Tx
GSM850 Rx
GSM900 Rx
GSM1800 Rx
GSM1900 Rx
UMTS1
UMTS2
Idle
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
TP1
15nH L106
C87
33p
1K R100
1K R101
1K R102
1K R103
Schematic of the Antenna Switch Block
Vc1
1.8-3.0V 1.8-3.0V
1.8-3.0V 0-0.2V
0-0.2V 0-0.2V
0-0.2V 0-0.2V
0-0.2V 1.8-3.0V
0-0.2V 1.8-3.0V
1.8-3.0V 0-0.2V
1.8-3.0V 0-0.2V
0-0.2V 0-0.2V
Logic Table of the Antenna Switch
4. TROUBLE SHOOTING
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
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
LMSP4LMA-573TEMP
Vc2 Vc3
0-0.2V
0-0.2V
0-0.2V
1.8-3.0V
1.8-3.0V
0-0.2V
1.8-3.0V
1.8-3.0V
0-0.2V
- 69 -
C88 56p
L111
56p
Vc4 Vdd
0-0.2V 2.4-3.0V
0-0.2V 2.4-3.0V
0-0.2V 2.4-3.0V
0-0.2V 2.4-3.0V
0-0.2V 2.4-3.0V
0-0.2V 2.4-3.0V
0-0.2V 2.4-3.0V
1.8-3.0V 2.4-3.0V
0-0.2V 0-0.2V
LGE Internal Use Only