供应1937

Features
z Inherently Matched LED Current
z Drives Up to Four LEDs from a 3.2V Supply z Drives Up to Six LEDs from a 5.0V Supply z High Efficiency: 85% Typical
z Fast 1MHz Switching Frequency
z 40V Internal Switch
z SOT-23-5L Pb-Free PACkaging
z Compatible with LT1937 and RT9271

Applications
z Cellular Phones
z MP3 Players
z PDAs, Hand-held Computers
z Digital Still Cameras
z GPS Receivers

General Description
The  1937  is  a  step-up  DC/DC  converter specifically designed to drive white LEDs with a constant current. The device can drive two, three or four LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED currents  resulting  in   uniform   brightness  and
eliminates  the  need  for  ballast  resistors.  The
1937 switches at 1MHz that allows the use of tiny    external    components.    A    low 300mV feedback voltage minimizes power loss in the current setting resistor for better efficiency.