LT3466

Features:

 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 (42V 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
Tiny (3mm ´ 3mm) 10-Lead DFN Package


Application

Main/Sub Displays
Digital Cameras, Sub-Notebook PCs
PDAs, Handheld Computers
Automotive


Specifications

Input Voltage (VIN) ................................................... 24V
SW1, SW2 Voltages ................................................ 44V
VOUT1, VOUT2 Voltages ............................................. 44V
CTRL1, CTRL2 Voltages ........................................... 24V
FB1, FB2, RT Voltages ................................................ 2V
Operating Temperature Range ................ 40°C to 85°C
Storage Temperature Range .................. 65°C to 125°C
Junction Temperature .......................................... 125°C

Description

LT®3466 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 a low profile, small footprint
(3mm ´ 3mm ´ 0.75mm) DFN package.