PMU Suits Cellular Phones

The LP3919 from National Semiconductor is a complete power management unit (PMU) IC designed for CDMA cellular phones. The PMU contains a Li-ion battery charger, nine low-noise low-dropout voltage regulators, two buck regulators, a USB transceiver, two comparators and a high-speed serial interface. The interface controls on/off conditions, programs output voltages and provides PMU-status information. A built-in overvoltage protection circuit at the charger input protects the PMU from input voltages up to +28 V, eliminating the need for any external protection circuitry. Offered in a 49-bump micro-SMD package, the LP3919 is $2.35 in 1000-unit quantities.