LP3925RME-E/NOPB

针对手机应用的高性能电源管理单元 High Performance Power Management Unit for Handset Applications

The LP3925 is designed to meet the power management requirements of the latest 3G/GSM/GPRS/EDGE cellular phones. The LP3925 PMU contains a single-input Li-Ion battery 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 charger. 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 operating from an AC adapter or USB power source.

The Li-Ion charger requires few external components and integrates 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 eliminating 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 output currents.

Buck regulators have an automatic switch to ECO mode at low load conditions providing very good efficiency at low output 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 information as well as two programmable alarms.

To accommodate different baseband requirements, the LP3925 PMU has different default voltage settings and startup sequences. Two general-purpose comparators can be used for detecting external accessories like ear-phones etc. Power conversion and signal level shifting circuits are provided to allow SIM interfacing.