LP3925 Datasheet, PDF (1/51 Pages) Texas Instruments – High Performance Power Management Unit for Handset Applications

LP3925
April 12, 2012
High Performance Power Management Unit for Handset
Applications
General Description
The LP3925 is designed to meet the power management re-
quirements of the latest 3G/GSM/GPRS/EDGE cellular
phones. The LP3925 PMU contains a single-input Li-Ion bat-
tery charger, 14 low-dropout voltage regulators including 3
wide-input, low-output, regulators, 3 buck regulators, a USB
Transceiver, two comparators, two TCXO buffers, SIM level
shifter, 12-bit ADC, real time clock, and backup battery charg-
er. Programming is handled via an I²C-compatible high-speed
Serial Interface allowing control of program on/off conditions
and the output voltages of individual regulators, and to read
status information of the PMU.
It can charge and maintain a single cell Li-Ion battery operat-
ing from an AC adapter or USB power source.
The Li-Ion charger requires few external components and in-
tegrates the power FET. Charging is thermally regulated to
obtain the most efficient charging rate for a given ambient
temperature.
A built-in Over-Voltage Protection (OVP) circuit at the charger
input protects the PMU from input voltages up to +28V elim-
inating the need for any external protection circuitry.
Buck regulators have an automatic switch to ECO mode at
low load conditions providing very good efficiency at low out-
put currents.
Buck regulators have an automatic switch to ECO mode at
low load conditions providing very good efficiency at low out-
put currents.
General-type “PERFECT” LDO regulators provide excellent
PSRR and ULTRA LOW NOISE, 10 µV typ., ideally suited for
supplying voltage to RF section.
The real-time clock/calendar provides time interval informa-
tion as well as two programmable alarms.
To accommodate different baseband requirements, the
LP3925 PMU has different default voltage settings and start-
up sequences. Two general-purpose comparators can be
used for detecting external accessories like ear-phones etc.
Power conversion and signal level shifting circuits are pro-
vided to allow SIM interfacing.
Features
■ ^{Linear charger with single input}
— USB or AC adapter input
— Power routing switch
— 28V OVP on the charger input
■ ^{Three high-efficiency Synchronous Magnetic Buck}
Regulators, I_OUT 800 mA each:
— 2 regulators have DVS support
— High-efficiency ECO mode @ low I_OUT
— Auto Mode ECO/PWM switch
— 28V OVP on the charger input
■ ^{15 LDOs}
— 10 General-type Low-Noise LDOs
8 x 300 mA
2 x 80 mA
— Three wide-input low-output (WILO) LDOs, all capable
of supplying up to 300 mA
— 1 micro-power LDO with I_OUT 30 mA
— 1 high-voltage USB LDO
— S/W controllable outputs
— Outputs configurable for pulldown
■ ^{Two Comparators and Two TCXO Buffers}
■ ^{USB 2.0-compatible Transceiver (12 Mb/s)}
■ ^{12-bit A/D Converter for battery management and external}
monitoring
■ ^{Two over-voltage protected outputs for USB transceivers}
■ ^{Real time clock with two alarms}
■ ^{SIM card level translator}
■ ^{Three controllable current sinks for Keypad LEDs}
■ ^{Backup battery charger}
■ ^{Thermal Shutdown with Early Warning Alarm}
■ ^{Momentary Power Loss detection}
■ ^{Interrupt Request to reduce S/W polling}
■ ^{81-bump micro SMDxt package}
Key Specifications
■ ^{LOW PMU I}_Q ^{in sleep mode}
■ ^{50 mA to 1200 mA Charging Current from AC Adapter}
■ ^{3.0V to 4.5V Battery Voltage}
■ ^{150 mV typ. Dropout Voltage on LDOs @ 300 mA}
■ ^{2% typ. Output Voltage accuracy on LDOs}
■ ^{ULTRA LOW NOISE (10 µV typ.), ULTRA LOW I}_Q^{, remote}
capacitor General-type “PERFECT” LDOs
■ ^{3% accurate Buck regulators up to 90% efficient}
Applications
■ ^{GSM, GPRS, EDGE, CDMA & 3G Handsets}
© 2012 Texas Instruments Incorporated 301204 SNVS672B
www.ti.com