LT3497 Dual Full Function White LED Driver with Integrated Schottky Diodes

Product Details

The LT3497 is a dual full function step-up DC/DC converter specifically designed to drive up to 12 white LEDs (6 white LEDs in series per converter) 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 and expensive factory calibration.

The two independent converters are capable of driving asymmetric LED strings. Accurate LED dimming and shutdown of the two LED strings can also be controlled independently. The LT3497 features a unique high side LED current sense that enables the part to function as a “one wire current source;” one side of the LED string can be returned to ground anywhere, allowing a simpler 1-wire LED connection. Traditional LED drivers use a grounded resistor to sense LED current, requiring a 2-wire connection to the LED string.

The 2.3MHz switching frequency allows the use of tiny inductors and capacitors. Few external components are needed for the dual white LED Driver: open-LED protection and the Schottky diodes are all contained inside the 3mm × 2mm DFN package. With such a high level of integration, the LT3497 provides a high efficiency dual white LED driver solution in the smallest of spaces.

Applications

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


Features and Benefits

  • Drives Up to 12 White LEDs (6 in Series per Converter) from a 3V Supply
  • Two Independent Boost Converters Capable of Driving Asymmetric LED Strings
  • Independent Dimming and Shutdown Control of the Two LED Strings
  • High Side Sense Allows “One Wire Current Source” per Converter
  • Internal Schottky Diodes
  • Open LED Protection (32V)
  • 2.3MHz Switching Frequency
  • ±5% Reference Accuracy
  • VIN Range: 2.5V to 10V
  • Dual Wide 250:1 True Color PWM Dimming
  • Requires Only 1µF Output Capacitor per Converter
  • Available in a 3mm × 2mm 10-Pin DFN Package