ZHCSCA8A March 2014 – April 2019 TPS65286
PRODUCTION DATA.
During startup, the output voltage follows up the voltage at the SS terminal to prevent inrush current. When the SS terminal voltage is less than the internal 0.6-V reference, the TPS65286 regulates the feedback voltage to the SS terminal voltage. The SS terminal can be used to program an external soft-start function or to allow output of the buck to track another supply during start-up. An internal pull-up current source of 5.5 µA charges an external soft-start capacitor to provide a ramping voltage at SS terminal. The TPS65286 will regulate the feedback voltage to the SS terminal voltage and VOUT rises smoothly from 0 V to its final regulated voltage. The soft-start time can be calculated by Equation 5:
With a floating SS terminal, there is default 1-ms (typical) soft-start time built in the chip.