The LTC3836 is a 2-phase dual output synchronous step-down switching regulator controller with tracking that drives external N-channel power MOSFETs using few external components. The constant-frequency current mode architecture with MOSFET VDS sensing eliminates the need for sense resistors and improves efficiency. The power loss and noise due to the ESR of the input capacitance are minimized by operating the two controllers out-of-phase. Pulse-skipping operation provides high efficiency at light loads. The 97% duty cycle capability provides low dropout operation, extending operating time in battery-powered systems.