DESCRIPTION
The LT®3755, LT3755-1 and LT3755-2 are DC/DC controllers designed to operate as a constant-current source for driving high current LEDs. They drive a low side external N-channel power MOSFET from an internal regulated 7.15V supply. The fixed frequency, current mode architecture results in stable operation over a wide range of supply and output voltages. A ground referenced voltage FB pin serves as the input for several LED protection features, and also makes it possible for the converter to operate as a constant-voltage source. A frequency adjust pin allows the user to program the frequency from 100kHz to 1MHz to optimize efficiency, performance or external component size.

FEATURES
■ 3000:1 True Color PWM™ Dimming
■ Wide Input Voltage Range: 4.5V to 40V
■ Output Voltage Up to 75V
■ Constant-Current and Constant-Voltage Regulation
■ 100mV High Side Current Sense
■ Drives LEDs in Boost, Buck Mode, Buck-Boost Mode,
   SEPIC or Flyback Topology
■ Adjustable Frequency: 100kHz to 1MHz
■ Open LED Protection
■ Programmable Undervoltage Lockout with Hysteresis
■ Improved Open LED Status Pin (LT3755-2)
■ Frequency Synchronization (LT3755-1)
■ PWM Disconnect Switch Driver
■ CTRL Pin Provides Analog Dimming
■ Low Shutdown Current: <1µA
■ Programmable Soft-Start
■ Thermally Enhanced 16-Lead QFN (3mm × 3mm)
   and MSOP Packages

APPLICATIONS
■ High Power LED
■ Battery Chargers
■ Accurate Current Limited Voltage Regulators