The TPS62097 programs its output voltage ramp rate with the SS/TR pin. Connecting an external capacitor to SS/TR enables output soft start-up to reduce inrush current from the input supply. The device charges the capacitor voltage to the input supply voltage with a constant current of typically 7.5 μA. The FB pin voltage follows the SS/TR pin voltage until the internal reference voltage of 0.8 V is reached. The soft start-up time is calculated using Equation 3. Keep the SS/TR pin floating to set the minimum start-up time.

Equation 3.

An active pulldown circuit is connected to the SS/TR pin. It discharges the external soft start-up capacitor in case of disable, UVLO, thermal shutdown, and HICCUP short circuit protection.