The LTC3714 is a synchronous step-down switching regulator controller for CPU power. An output voltage between 0.6V and 1.75V is selected by a 5-bit code (Intel mobile VID specification). The controller uses a constant on-time, valley current control architecture to deliver very low duty cycles without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in VIN and VOUT. Discontinuous mode operation provides high efficiency operation at light loads. A forced continuous control pin reduces noise and RF interference and can assist secondary winding regulation by disabling discontinuous mode when the main output is lightly loaded. Internal op amp allows programmable offsets to the output voltage during power saving modes.