The LT3757 operates over an input voltage from 2.9V to 40V while the LT3758 accepts an input voltage from 5.5V to 100V. These parts are unique in that they have two internal voltage feedback error amplifiers and reference voltages. One set is for positive output voltages, with a 1.60V reference voltage, and the other for negative output voltages, with a -0.80V reference voltage, both off the same single feedback pin. Both parts have a programmable fixed or synchronizable operating frequency from 100kHz to 1MHz, allowing designers to choose from a wide range of inductors and capacitors to optimize size, performance and cost. Their current-mode control results in stable operation over a wide range of supply and output voltages. Designs utilizing ceramic capacitors offer the smallest solution size with efficiencies up to 96% being achievable. The LT3757/LT3758 drives a low side external N-channel MOSFET from an internally regulated 7.2V supply. The programmable soft-start feature allows for a controlled current ramp and output voltage turn-on time. In addition, the LT3757/LT3758 features a programmable input undervoltage lockout with hysteresis, along with output overvoltage and overcurrent protection. These devices are available in thermally enhanced MSOP-10 and 3mm x 3mm DFN-10 packages.