General Description
The RT9271 is a step-up DC/DC converter specifically designed to drive white LEDs with a constant current. The device can drive one to three LEDs in series from a Li-Ion cell. Series connection of the LEDs providesidentical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The RT9271 switches at 1.1 MHz, allowing the use of tiny external components. The input and output capacitor can be as small as 1uF, saving space and cost versus alternative solutions. A low 0.25V feedback voltage minimizes power loss in the current
setting resistor for better efficiency.

FEATUREs
Inherently Matched LED Current
Up to 80mA Output Current @ VOUT< 12V
High Efficiency : 85% Typical
Drives Up to Three LEDs from 2.8V Supply
20V Internal Switch
Fast 1.1 MHz Switching Frequency
Uses Tiny 1 mm Height Inductors
Requires Only 1uF Output Capacitor
Low Profile SOT-23-6 Package
Optional 15V Over Voltage Protection
RoHS Compliant and 100% Lead (Pb)-Free

Applications
Mobile Phone
Digital Still Camera
PDAs, Handheld Computers
MP3 Players
GPS Receivers