General Description

The MAX868 inverting charge pump provides a low-cost and compact means of generating a regulated negative voltage up to -2 x VIN from a positive input voltage between 1.8V and 5.5V. It uses a pulse-frequencymodulation (PFM) control scheme to generate the regulated negative output voltage. PFM operation is obtained by gating the internal 450kHz oscillator on and off as needed to maintain output voltage regulation. This unique on-demand switching scheme gives the MAX868 excellent light-load efficiency without degrading its fullload operation (up to 30mA), permitting smaller capacitors to take advantage of the oscillator’s high switching frequency.

Features

♦ Regulated Negative Output Voltage (up to -2 x VIN)

♦ Ultra-Small, 10-Pin µMAX Package

♦ On-Demand Switching at up to 450kHz

♦ 30µA Quiescent Supply Current

♦ Requires Only Four Small External Capacitors

♦ 1.8V to 5.5V Input Voltage Range

♦ 0.1µA Logic-Controlled Shutdown

♦ Up to 30mA Output Current

Applications

   Small LCD Panels

   Cell Phones

   Cordless Phones

   Camcorders

   Handy-Terminals, PDAs

   Medical Instruments

   Battery-Operated Equipment