The LTC3809-1 is a synchronous step-down switching regulator controller that drives external complementary power MOSFETs using few external components. The constant frequency current mode architecture with MOSFET VDS sensing eliminates the need for a current sense resistor and improves efficiency. Optional Burst Mode operation provides high efficiency operation at light loads. 100% duty cycle provides low dropout operation, extending operating time in battery powered systems. Burst Mode is inhibited when the MODE pin is pulled low to reduce noise and RF interference. The LTC3809-1 allows either coincident or ratiometric output voltage tracking. Switching frequency is fixed at 550kHz. Fault protection is provided by an overvoltage comparator and a short-circuit current limit comparator. The LTC3809-1 is available in the tiny footprint thermally enhanced DFN and 10-lead MSOP packages.
