13Mhz Clock; Power Supplies For Rf Circuits - LG C1100 Service Manual

3.3 13MHz Clock (VCTCXO, X301)
The 13 MHz clock(X301) consists of a TCXO(Temperature Compensated Crystal Oscillator)
which oscillates at a frequency of 13 MHz. It is used within the Si4205, analog base band
chipset (U102, AD6537B), digital base band chipset (U101, AD6525), and MIDI (U401) chipset.
VVCXO
C371
2.2u
1608
3.4 Power Supplies for RF Circuits (RF LDO, U303)
Two regulators are used for RF circuits. One is MIC5255 (U303), and the other is one port of
AD6537B (U102).
MIC5255 (U303) supplies power to transceiver (SI4205, U301).
One port of AD6537B supplies power to VCTCXO (X301).
Main power (VBAT) from battery is used for PAM (RF3133, U302) because PAM requires high
power.
Supplier
U303 (VRF)
U102 (VVCX0)
Battery (VBAT)
X301
3
OUT
4 2
VCC GND
13MHz
Figure 3-6. VCTCXO CIRCUIT DIAGRAM
Table 3-2. RF POWER SUPPLIERS
Voltage
2.85V
2.75V
3.4~4.2V
VRF
MIC5255-2.85BM5
5
OUT
C363
4
C362
BYP
10u 0.01u
Figure 3-7. RF LDO CIRCUIT DIAGRAM
R317
15K
C372
1000p
Powers
U301, U302
X301
U302,U303
VBAT
U303
1
IN
2
GND
3 R317
EN
C361 10u
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3. TECHNICAL BRIEF
AFC AD6535_AFCDAC
Enabled signal
CLKON
0
CLKON