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4. TROUBLE SHOOTING
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4.4 Checking VC-TCXO Block
The reference frequency (19.2MHz) from X100 (VC-TCXO) is used in UMTS
TX part, GSM part and BB part.
TCXO
24
VCC
5
TC7SH04FU
U104
GND
3
100pC185
0.1u
C181
R124100ohm
1000p
C182
R128 100K
C183
0.01u
1000p
C186
DSA321SCE-19.2M
X100
GND
2
5
NC1
NC2
67
NC3
NC4
8
OUTPUT
3
4
VCC
1
VCONT
19.2MHz
0.01uC188C187 1000p
VREG_TCXO_2.85V
TRK_LO_ADJ
TCXO_BT
VREG_BT_2.85V
TCXO_PM
RTR6275_TCXO
TP2
TP1
TP3
TP4
Schematic of the VC-TCXO Block
Test Point of the VC-TCXO Block
TP1
TP4
TP3
TP2