The DC385 is a high density synchronous step-down (buck) regulator using the LTC®1778 No RSENSE™ switching regulator controller. This controller uses a valley current control architecture to deliver very low duty cycles without requiring a sense resistor. It provides high efficiency operation at light loads by means of discontinuous mode operation. Noise and RF interference are reduced by means of a forced continuous control pin. The circuit uses a dual SyncFET™ and has a very small footprint. With a wide operating range of VIN from 5V to 28V and a duty cycle of 2% to 90% at 200kHz, the circuit demonstrates that the LTC1778 is ideal for applications such as notebook and palmtop computers, PDAs, battery chargers and distributed power systems.