General Description

The FAN4855 is a low power boost regulator designed for low voltage DC to DC conversion in 2-cell battery powered systems such as digital cameras, cell phones and PDAs. The converter starts-up at 1.3V and operates after the start at an input voltage as low as 1V. Output voltage can be adjusted by external resistors from 3.3V to 5V with a maximum load current of 0.5A. Quiescent current in shut-down mode is less than 10µA, which maximizes the battery live time.

Features

■ Low power PFM boost regulator

■ Input voltage range is from 1.6V to 4.5V

■ Output voltage range is from 3V to 5V

■ 500mA maximum load current capability

■ 95 efficient power conversion

■ 2-3 cell and single cell Li-Ion systems

■ Variable on-time Pulse Frequency Modulation (PFM)

■ Internal synchronous rectifier (no need for external diode)

■ Low-battery detection

■ Logic controlled shutdown with true-load disconnect

■ Low (80µA) quiescent current

■ TSSOP-8 Package

Applications

■ DSCs

■ PDAs

■ Cell phones, smart phones

■ Portable instrumentations

■ 2-3 AA / AAA cells operated devices

■ Single cell Li-Ion operated devices