The LTC3772 is a constant frequency current mode step-down DC/DC controller in a low profile 8-lead SOT-23 (ThinSOT) and a 3mm × 2mm DFN package. The No RSENSE architecture eliminates the need for a current sense resistor, improving efficiency and saving board space. The LTC3772 automatically switches into Burst Mode operation at light loads to increase efficiency at low output current. It consumes only 40µA of quiescent current under a no-load condition. The LTC3772 incorporates an undervoltage lockout feature that shuts down the device when the input voltage falls below 2V. To maximize the runtime from a battery source, the external P-channel MOSFET is turned on continuously in dropout (100% duty cycle). High switching frequency of 550kHz allows the use of a small inductor and capacitors. An internal soft-start smoothly ramps the output voltage from zero to its regulation point.
