The LTC3717 is a synchronous step-down switching regulator controller for double data rate (DDR) and Quad Data RateTM (QDRTM) memory termination. The controller uses a 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. Forced continuous operation reduces noise and RF interference. Output voltage is internally set to half of VREF, which is user programmable.