LG B2100, Service Manual

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Service Manual /
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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, AD6537BABC),
digital base band chipset (U100, AD6527B). MIDI Chip (U203, ML287HB), Camera Chip (U601, CL761s)
3.4 Power Supplies for RF Circuits (RF LDO, U502)
Two regulators are used for RF circuits. One is MIC5255 (U502), and the other is one port of AD6537
(U101).
MIC5255 (U502) supplies power to transceiver (SI4205, U500). One port of AD6537 supplies power to
VCTCXO (X500). Main power (VBAT) from battery is used for PAM (RF3166, U501) because PAM requires
high power.
Table 3-2 RF POWER SUPPLIERS
Figure 3-6 VCTCXO CIRCUIT DIAGRAM
Supplier Voltage Powers enabled signal
U502(VRF) 2.85 V U500 CLKON
U101(VVCXO) 2.75 V X500
Battery(VBAT) 3.4 ~ 4.2 V U501