MAX847

19-1349; Rev 1a; 10/98 L MANUA ION KIT HEET T A U L EVA TA S WS DA FOLLO 1-Cell, Step-Up Two-Way Pager System IC ____________________________Features o 80mA Output from 1 Cell at 90% Efficiency o 13µA Idle Mode™ (coast) Current o Selectable Low-Noise PWM or Low-Current Operation o PWM Operating Frequency Synchronized to Seven Times an External Clock Source o Operates at 270kHz with No External Clock o Automatic Backup-Battery Switchover ________________General Description 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 softwaredriven 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 1.8 Ω (typical) serial-controlled open-drain MOSFET switches An evaluation kit for the MAX847 (MAX847EVKIT) is available to aid in design and prototyping. Pin Configuration appears at end of data sheet. MAX847 Ordering Information PART MAX847EEI TEMP. RANGE -40°C to +85°C PIN-PACKAGE 28 QSOP ________________________Applications Two-Way Pagers GPS Receivers 1-Cell Powered Hand-Held Equipment __...