13 Mhz Clock; Power Supplies Of Rf Circuits - LG B2070 Service Manual

3. TECHNICAL BRIEF
3.3 13 MHz Clock (VCTCXO, X500)
The 13 MHz clock(X500) 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
(U101, AD6537B), digital base band chipset (U100, AD6527).
3.4 Power Supplies for RF Circuits (RF LDO, U702)
Two regulators are used for RF circuits. One is MIC5255 (U702), and the other is one port of
AD6537B (U101).
MIC5255 (U702) supplies power to transceiver (SI4205, U500). One port of AD6537B supplies
power to VCTCXO (X500).
Supplier
U702(VRF)
U101(VVCXO)
Battery(VBAT)
2V75_VVCXO
3
OUT VCONT
4
VCC
ONG
C536
13MHz
22u
Figure 3-6 VCTCXO CIRCUIT DIAGRAM
Voltage
2.85 V
2.75 V
3.4 ~ 4.2 V
Table 3-2 RF POWER SUPPLIERS
- 20 -
X500
R516
1
C538 15K
2
1000p
Powers
U500
X500
U501, U702
APC
enabled signal