When Enable (EN) is set High, the device starts operation. Shutdown is forced if EN is pulled Low with a shutdown current of typically 1.5µA. During shutdown, the internal power MOSFETs as well as the entire control circuitry are turned off. The internal resistive divider pulls down the output voltage smoothly. The EN signal must be set externally to High or Low. The typical threshold values are 0.65V (rising) and 0.45V (falling). An internal pull-down resistor of about 400kΩ is connected and keeps EN logic low, if Low is set initially and then the pin gets floating. It is disconnected if the pin is set High.
Connecting the EN pin to an appropriate output signal of another power rail provides sequencing of multiple power rails.