LG CU920 - Page 93

- 95 -
4. TROUBLE SHOOTING
LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Fig. 4.6.3 Logic Table of the FEM
Check Soldering of
ANT_SEL0,1,2,3 High Level
Check the Logic
in each mode
1.8V < Voltage < 3.0V
Check VCC
TPI VREG_RF_2.85V
NO
YES
Fig. 4.6.4 Check Flow of the FEM
Mode Vc1 Vc2 Vc3 Vc4 Vdd
GSM850/900 Tx 1.8-3.0V 1.8-3.0V 0-0.2V 0-0.2V 2.4-3.0V
GSM1800/GSM1900 Tx 1.8-3.0V 0-0.2V 0-0.2V 0-0.2V 2.4-3.0V
GSM850 Rx 0-0.2V 0-0.2V 0-0.2V 0-0.2V 2.4-3.0V
GSM900 Rx 0-0.2V 0-0.2V 1.8-3.0V 0-0.2V 2.4-3.0V
GSM1800 Rx 0-0.2V 1.8-3.0V 1.8-3.0V 0-0.2V 2.4-3.0V
GSM1900 Rx 0-0.2V 1.8-3.0V 0-0.2V 0-0.2V 2.4-3.0V
UMTS1 1.8-3.0V 0-0.2V 1.8-3.0V 0-0.2V 2.4-3.0V
UMTS2 1.8-3.0V 0-0.2V 1.8-3.0V 1.8-3.0V 2.4-3.0V
Idle 0-0.2V 0-0.2V 0-0.2V 0-0.2V 0-0.2V
CONTROL LOGIC