Dual Full Function White LED Step-Up Converter with Built-In Schottky Diodes

LT3466 is a dual full function step-up DC/DC converter specifically designed to drive up to 20 White LEDs (10 in series per converter) with a constant current. 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. The dimming of the two LED strings can also be controlled independently. The LT3466 is ideal for providing backlight for main and sub-displays in cell phones and other handheld devices.

The LT3466 operating frequency can be set with an external resistor over a 200kHz to 2MHz range. A low 200mV feedback voltage minimizes power loss in the current setting resistor for better efficiency. Additional features include output voltage limiting when LEDs are disconnected and internal soft-start.

The LT3466 is available in the 10-pin (3mm × 3mm × 0.75mm) DFN and 16-pin thermally enhanced TSSOP packages.

Applications

* Main/Sub Displays

* Digital Cameras, Sub-Notebook PCs

* PDAs, Handheld Computers

* Automotive

* Drives Up to 20 White LEDs (10 in Series per Converter) from a 3.6V Supply

* Two Independent Step-Up Converters Capable of Driving Asymmetric LED Strings

* Independent Dimming and Shutdown Control of the Two LED Strings

* Internal Schottky Diodes

* Internal Soft-Start Eliminates Inrush Current

* Open LED Protection (39.5V Max VOUT)

* Fixed Frequency Operation Up to 2MHz

* 81% Efficiency Driving 16 White LEDs at 15mA (Eight per Driver) from a 3.6V Supply

* Wide Input Voltage Range: 2.7V to 24V

* Available in 10-Pin DFN and 16-Pin Thermally Enhanced TSSOP Packages