Checking Vctcxo Block - LG U970 Service Manual

4.4 Checking VCTCXO Block

The reference frequency (19.2MHz) from X100 (VCXO) is used in UMTS TX
part, GSM part and BB part.
TP1
VREG_TCXO_2.85V
C147
0.1u
TP4
C151
TCXO_PM
C155
RTR6275_TCXO
TP3
X100
OUT
3
VCC VCONT
4
19.2MHz
C148
TCXO
1000p
1000p
1000p C156 8200p
Rev. F
Schematic of the TCXO Block
TP3 TP4
Test Point of the TCXO Block
- 81 -
4. TROUBLE SHOOTING
GND
2
R113 100ohm
1
C149
0.01u
R118 100K
U102
TC7SH04FS
TP1
TP2
TRK_LO_ADJ
VREG_BT_2.85V
C153
1000p
TCXO_BT
TP2