The BU9000xGWZ are high efficiency 6MHz synchronous step-down switching regulators with low-current Pulse Frequency Modulation mode. It supports up to 1.0A load current with an input voltage range of 3.0V to 5.5V – optimized for portable battery-powered applications. It has a mode control pin that allows the user to select Forced PWM (Pulse Width Modulation) mode or PFM (Pulse Frequency Modulation); auto PWM switching mode utilized to save power at light loads.