JAJSJT8C May 2020 – June 2021 TPS543620
During start-up, the device softly ramps the reference voltage to reduce inrush currents. There are four options for the soft-start time, which is the time it takes for the reference to ramp to 0.5 V: 0.5 ms, 1 ms, 2 ms, and 4 ms. The soft-start time is selected with a resistor to AGND on the MODE pin (see Section 7.3.8).
The device prevents current from being discharged from the output during start-up when a prebiased output condition exists. It does this by operating in discontinuous conduction mode (DCM) during the first 16 cycles to prevent the device from sinking current. This ensures the output voltage will be smooth and monotonic during soft start.