Demonstration circuit 1315 features the LT®3475-1 dual step-down 1.5A LED driver in a 16-lead TSSOP thermally enhanced package. The demonstration circuit is designed to drive two 1.5A 4-LED strings (one on each channel) from an input voltage between 13V and 36V, but the start-up voltage is limited to 30V. The LT3475-1 operates from 4V to 36V so a lower input voltage can be applied with fewer LEDs.