DESCRIPTION
The LT®3518 is a current mode DC/DC converter with an internal 2.3A, 45V switch specifically designed to drive LEDs. The LT3518 operates as a LED driver in boost, buck mode and buck-boost mode. It combines a traditional voltage loop and a unique current loop to operate as a constant-current source or constant-voltage source. Programmable switching frequency allows optimization of the external components for efficiency or component size. The switching frequency of the LT3518 can be synchronized to an external clock signal. The LED current is externally programmable with a 100mV sense resistor. The external PWM input provides 3000:1 LED dimming. The CTRL pin provides further 10:1 dimming ratio.

FEATUREs
■ 3000:1 True Color PWM™ Dimming Ratio
■ 2.3A, 45V Internal Switch
■ 100mV High Side Current Sense
■ Open LED Protection
■ Adjustable Frequency: 250kHz to 2.5MHz
■ Wide Input Voltage Range:
   ■ Operation from 3V to 30V
   ■ Transient Protection to 40V
■ Operates in Boost, Buck Mode and Buck-Boost Mode
■ Gate Driver for PMOS LED Disconnect
■ Constant-Current and Constant-Voltage Regulation
■ CTRL Pin Provides 10:1 Analog Dimming
■ Low Shutdown Current: <1µA
■ Available in (4mm × 4mm) 16-Lead QFN and 16-Pin
   TSSOP Packages

APPLICATIONS
■ Display Backlighting
■ Automotive and Avionic Lighting
■ Illumination
■ Scanners