LG KG110 - Getting Started with KG110; Installing the SIM Card and Battery

3. TECHNICAL BRIEF
3.2.4 Power Management
For direct battery supply connect, and to reduce external circuitry complexity the AD6548/9
features three Low Drop Out Regulators (LDOs). The three LDOs provide isolation of the
oscillators and sensitive circuits from unwanted power supply and cross coupled noise.
They also ensure the IC operation is robust over a wide range of power supply voltages.
For power management the LDOs are independently controlled via the 3 wire serial bus.
A.LDO Usage
The following table describes the LDO usage:
14
LDO1 LDO2 LDO3
Rx and Tx baseband Main VCO TX VCO
sections
LDO OP External Connection
VLDO1 VCC_FE, VCC_BBI, VCC_BBQ
VLDO2 No external Connections, except for decoupling
VLDO3 No external Connections, except for decoupling
Table 3-2: Intended LDO Use
Table 3-3: LDO Connections
The LDO outputs require external connection to the respective pins described in table 3, and
each requires decoupling capacitors.The LDOs are designed to be unconditionally stable
regardless of the capacitor's ESR.
LDO1 derives its input references from the crystal supply voltage (VCC_REF).
It is therefore expected that VCC_REF be supplied from a external LDO of nominal supply
voltage 2.75V
(e.g. ADP3330 or Analog Baseband IC: Vout=2.75V 1.4%)