SLUSDW9A June 2020 – June 2020 TPS51215A
Prior to asserting EN high, the power stage conversion voltage and V5IN voltage should be ready. When EN is asserted high, TPS51215A provides soft start to suppress in-rush current during start-up. The soft start action is achieved by an internal SLEW current of 4.5 µA (typ) sourcing into a external MLCC capacitor connected from SLEW pin to GND.
Use Equation 1 to determine the soft-start timing.
The TPS51215A has a open-drain PowerGood output pin that indicates the Vout voltage is within the target range. The target voltage window and transition delay times of the PGOOD comparator are ±8% (typ) and 1-ms delay for assertion from low to high, and ±16% (typ) and 0.2-µs delay for de-assertion from high to low during operation.