
Fairchild Semiconductor
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