13Mhz Clock; Power Supplies And Control Signals - LG 512W Service Manual

3.4 13MHz Clock

The 13 MHz clock (VC-TCXO-208C) consists of a TCXO (Temperature Compensated Crystal
Oscillator) which oscillates at a frequency of 13 MHz.
It is used within the Si4133G_XM2 Synthesizers, BB Analog chip-set (AD6521), and Digital
(AD6522). The inverter IC, SN74AHC1GU04 buffer the output to AD6521, AD6522 and
Si4133G_XM2.

3.5 Power Supplies and Control Signals

There are two regulators used in the phone to provide RF power. One is contained inside of
ADP3408 (U1), power management IC to provide the power for the VCTXO (X302). The other is
used to provide the power for remaining RF circuits.
Regulator
Regulator 1 (U1, 2V7_VTCXO)
Regulator 2 (U309, RF2V8)
Figure 3-8. VCTCXO Circuit.
Table 3-7. Power Supplies
Voltage
2.7 V 0.5 V
2.85 V 0.5 V
Figure 3-9. Regulator Circuit.
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3. TECHNICAL BRIEF
Powers Enable Signal
VCTXO
RF circuitry VSYNTHEN