Power Supply 28-Pin QSOP

The MAX847 is a complete power-supply and monitoring system for two-way pagers or other low-power digital communications devices. It requires few external components. Included on-chip are: A 1-cell input, 80mA output, synchronous-rectified boost DC-DC regulator with a digitally controlled +1.8V to +4.9V output Three low-noise linear-regulator outputs Three DAC-controlled comparators for software- driven 3-channel A/D conversion SPI-compatible serial interface Reset and low-battery (LBO) warning outputs Charger for NiCd, NiMH, lithium battery, or storage capacitor for RF PA power or system backup Two 1.8O (typical) serial-controlled open-drain MOSFET switches An evaluation kit for the MAX847 (MAX847EVKIT) is available to aid in design and prototyping.

• 80mA Output from 1 Cell at 90% Efficiency
• 13µA Idle Mode (coast) Current
• Selectable Low-Noise PWM or Low-Current Operation
• PWM Operating Frequency Synchronized to Seven Times an External Clock Source
• Operates at 270kHz with No External Clock
• Automatic Backup-Battery Switchover