The California Micro Devices' SmartORTM CMPWR101 is a low dropout regulator that delivers up to 250mA of load current at a fixed 3.3V output. An internal threshold level (typically 4.1V) is used to prevent the regulator from being operated below dropout voltage. The device continuously monitors the input supply and will automatically disable the regulator when VCC falls below the threshold level. When the regulator is disabled, a low impedance, fully integrated switch is enabled which allows the output to be directly powered from an auxiliary 3.3V supply.