LG KG920 - 26 Mhz Clock (VCTCXO); Power Supplies for RF Circuits (RF LDO)

3. TECHNICAL BRIEF
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3.3 26 MHz Clock (VCTCXO)
The 26 MHz clock(X501) consists of a TCXO(Temperature Compensated Crystal Oscillator) which
oscillates at a frequency of 26 MHz. It is used within the Si4210, analog base band chipset (U100, AD6535),
digital base band chipset (U101, AD6527)
3.4 Power Supplies for RF Circuits (RF LDO)
Two regulators are used for RF circuits. One is MIC5255 (U504), and the other is one port of AD6535
(U100).
MIC5255 (U504) supplies power to transceiver (SI4210, U502). One port of AD6535 supplies power to
VCTCXO (X501). Main power (VBAT) from battery is used for PAM (SKY77328, U501) because PAM
requires high power.
(AFCDAC)
4
VCONT
1
26MHz
X501
2
GND
3
OUT
VCC
15K
R523
C548
1000p
2V75_VVCXO
C549
2.2u
AFC
Figure 3-5 VCTCXO CIRCUIT DIAGRAM
Supplier Voltage Powers Enabled signal
U504(VRF) 2.85 V U502 CLKON
U100(VVCXO) 2.75 V X501
Battery(VBAT) 3.4 ~ 4.2 V U501, U504
Table 3-2 RF POWER SUPPLIERS
26MHz