The LTC3731 is a PolyPhase®synchronous step-down switching regulator controller that drives all N-channel external power MOSFET stages in a phase-lockable fixed frequency architecture. The 3-phase controller drives its output stages with 120° phase separation at frequencies of up to 600kHz per phase to minimize the RMS current losses in both the input and output filter capacitors. The 3-phase technique effectively triples the fundamental frequency, improving transient response while operating each controller at an optimal frequency for efficiency and ease of thermal design. Light load efficiency is optimized by using a choice of output Stage Shedding or Burst Mode operation.A differential amplifier provides true remote sensing of both the high and low side of the output voltage at the point of load. The precision reference supports output voltages from 0.6V to 6V.Soft-start and a defeatable, timed short-circuit shutdown protect the MOSFETs and the load. Current foldback provides protection for the external MOSFETs under short-circuit or overload conditions.ApplicationsDesktop Computers and ServersHigh Performance Notebook ComputersHigh Output Current DC/DC Power Supplies