LT1937 - White LED Step-Up Converter in SC70 and ThinSOT

The LT1937 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 eliminating the need for ballast resistors. The LT1937 switches at 1.2MHz, allowing the use of tiny external components. The output capacitor can be as small as 0.22µF, saving space and cost versus alternative solutions. A low 95mV feedback voltage minimizes power loss in the current setting resistor for better efficiency.

The LT1937 is available in low profile SC70 and ThinSOT packages.

Features

Inherently Matched LED Current
High Efficiency: 84% Typical
Drives Up to Four LEDs from a 3.2V Supply
Drives Up to Six LEDs from a 5V Supply
36V Rugged Bipolar Switch
Fast 1.2MHz Switching Frequency
Uses Tiny 1mm Tall Inductors
Requires Only 0.22µF Output Capacitor
Low Profile SC70 and ThinSOT™ Packaging

Typical Application

Applications

Cellular Phones
PDAs, Handheld Computers
Digital Cameras
MP3 Players
GPS Receivers

Packaging

Order Information

Part Number	Package	Temp	Price(1-99)	Price (1k)*
LT1937ES5#PBF	SOT-23	E	$1.86
LT1937ES5#TRMPBF	SOT-23	E	$1.86	$1.38
LT1937ES5#TRPBF	SOT-23	E	$1.86	$1.36
LT1937ESC6#PBF	SC-70	E	$2.14
LT1937ESC6#TRMPBF	SC-70	E	$2.14	$1.53
LT1937ESC6#TRPBF	SC-70	E	$2.14	$1.51

Demo Boards

Part Number	Description	Price
DC484A	LT1937ES5 \| Single Cell White LED(4) Driver with On-Board Battery, Vin 2.7V - 5V	$75.00
DC507A	LT1937ESC6 \| 2-Ckt, High Efficiency Constant-Current Single Cell Li-Ion White LED (4) Driver with On-Board Battery	$75.00