LG CU920 Manual page 93

CONTROL LOGIC
Mode
GSM850/900 Tx
GSM1800/GSM1900 Tx
GSM850 Rx
GSM900 Rx
GSM1800 Rx
GSM1900 Rx
UMTS1
UMTS2
Idle
Check Soldering of
ANT_SEL0,1,2,3 High Level
1.8V < Voltage < 3.0V
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Vc1
1.8-3.0V 1.8-3.0V
1.8-3.0V
0-0.2V
0-0.2V
0-0.2V 1.8-3.0V
0-0.2V 1.8-3.0V
1.8-3.0V
1.8-3.0V
0-0.2V
Fig. 4.6.3 Logic Table of the FEM
YES
Check the Logic
in each mode
Fig. 4.6.4 Check Flow of the FEM
4. TROUBLE SHOOTING
Vc2 Vc3
0-0.2V
0-0.2V 0-0.2V
0-0.2V 0-0.2V
0-0.2V 1.8-3.0V
1.8-3.0V
0-0.2V
0-0.2V 1.8-3.0V
0-0.2V 1.8-3.0V
0-0.2V 0-0.2V
NO
Check VCC
TPI VREG_RF_2.85V
- 95 -
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