The LT3518 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 and buck-boost modes. 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. The LT3518 is available in the tiny footprint 16-Lead QFN (4mm × 4mm) and the 16-Pin TSSOP package. The LT3518 provides a complete solution for both constant-voltage and constant-current applications.