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3. TECHNICAL BRIEF
DC/DC Step Down Converter for 1.8V (SD1)
The DC/DC converter generates a 1.8V supply rail. This voltage rail is used to supply main parts of the
system, like the digital core of the chip (via LDO LCORE), some parts of the mixed signal macro, parts of the
RF macro and the external memory if a 1.8V memory is used. The efficiency of the DC/DC converter is
optimized for an average load current of 100mA. That is the load current estimated for the GSM talk mode.
Linear voltage Regulators (low dropout) LDOs
The LDOs are used to generate the supply for the different supply domains not directly supplied out of
the DC/DC converter.
The VSIM output current is high enough to drive USB SIM cards.
LCORE
The LCORE LDO provides the VCORE supply used for most of the digital parts of the chip
LPMU
The LPMU provides VPMU sued for the PMU supply, e.g. for the startup state machine and analog parts like
ADC, sense amplifier etc.
LUSB
The LUSB LDO generates the supply for the USB transceiver (output driver and input). If no USB interface is
required, LUSB can be used as general purpose LDO.
LAUX
The LAUX generates VAUX. It is a general purpose LDO and can be used for different functions depending
on the phone application, e.g. for the display or Camera.
LMMC
The LMMC generates VMMC. It is a general purpose LDO and can be used e,g. for memory cards
LSIM
The LSIM LDO generates the VSIM supply for the SIM card and interface. It is designed to supply Standard
SIM cards.
Other LDOs
The RF module has implemented several LDO's for different RF Power domain.
The mixed signal module has some LDO's for the audio driver and microphone supply.
LGE Internal Use Only
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Copyright © 2010 LG Electronics. Inc. All right reserved.
3. TECHNICAL BRIEF
Only for training and service purposes
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