Power Management - LG A395 Service Manual

3.2 Power Management

3.2 Power Management
The power management unit(PMU) manages the power supply of the entire chip, such as baseband,
processor, memory, SIM cards, camera, vibrator, etc. The digital part of PMU is integrated into the analog
part. PMU includes the following functions for signal processing:
3.2.1 Low Dropout Regulators(LDOs), Buck converter and Reference
The PMU Integrates 14 LDOs and 1 buck converter(BUCK) that are optimized for their given functions by
balancing quiescent current, dropout voltage, line/load regulation, ripple rejection, and output noise
▪ RF LDO (VRF)
The RF LDO is a linear regulator that could source 200mA (max) with 2.8V output voltage. It
supplies the RF circuitry of the handset. The LDO is optimized for high performance and adequate
quiescent current.
▪ Digital Core Buck Converter (VCORE)
The digital core regulator is a DC-DC step-down converter (Buck converter) that could source
350mA (max) with 1.3V to 0.9V programmable output voltage based on software register setting.
It supplies the power for baseband circuitry of the SoC. The buck converter is optimized for high
efficiency and low quiescent current.
Digital IO LDO (VIO18)
The digital IO LDO is a linear regulator that could source 100mA (max) with 1.8V output voltage. It
supplies the power for baseband circuitry of the SoC. The LDO is optimized for very low quiescent
current and turns on automatically together with Vm/Va LDOs.
 Analog LDO (VA)
The analog LDO is a linear regulator that could source 40mA (max) with 2.8V output voltage. It
supplies the analog sections of the SoC. The LDO is optimized for low frequency ripple rejection in
order to reject the ripple coming from the burst at 217Hz of RF power amplifier.
TCXO LDO (VTCXO)
The TCXO LDO is a linear regulator that could source 40mA (max) with 2.8V output voltage. It
supplies the temperature compensated crystal oscillator, which needs ultra low noise supply with
very good ripple rejection.
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LGE Internal Use Only
3. TECHNICAL BRIEF
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Only for training and service purposes
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3. TECHNICAL BRIEF
Only for training and service purposes