The AX3771 is a dual high-efficiency Pulse-Skipping-Modulated (PSM) step-down DC-DC converter. It is capable of delivering 1A output current over a wide input voltage range from 2.5V to 7.5V, the AX3771 is ideally suited for portable electronic devices that are powered from 1-cell Li-ion battery or from other power sources within the range such as cellular phones, PDAs and other handheld devices.

Two operational modes are available: PSM/Low-Dropout auto-switch and shutdown modes. Internal synchronous rectifier with low RDS(ON) dramatically reduces conduction loss at PSM mode. No external Schottky diode is required in practical application.

The AX3771 enters Low-Dropout mode when normal PSM cannot provide regulated output voltage by continuously turning on the upper PMOS. The AX3771 enter shutdown mode and consumes less than 0.1μA when EN pin is pulled low.

The switching ripple is easily smoothed-out by small package filtering elements due to a fixed operation frequency of 1.4MHz. This along with small TDFN-12L (3x3) package provides small PCB area application. Other features include soft start, lower internal reference voltage with 2% accuracy, over temperature protection, and over current protection.