The converter is in active mode whenever the EN/SYNC voltage is above the threshold voltage, V_IN, is high enough to satisfy V_{IN_OPERATE}, and no other fault conditions are present. The simplest way to enable operation is to connect EN/SYNC to VIN, which allows self start-up when the applied input voltage exceeds the minimum V_{IN_OPERATE}.

In active mode, depending on the load current, input voltage, and output voltage, the converter is in one of five modes:

• Continuous conduction mode (CCM) with fixed switching frequency when the load current is above half of the inductor current ripple.
• AUTO mode – Light-load operation with PFM where the switching frequency decreases at very light load.
• FPWM mode – Light-load operation that maintains constant switching frequency across the full load range.
• Minimum on time: The switching frequency reduces to maintain regulation with high step-down conversion ratios, that is, high input voltage to low output voltage.
• Dropout mode: The switching frequency reduces to minimize the dropout voltage.