SLVSCO4D July 2015 – February 2019 TPS65917-Q1
Texas Instruments recommends to always power down the TPS65917-Q1 before removing power from VCCA. If the input voltage to the device is removed while the device is ACTIVE, the device will shut off when VCCA reaches the VSYS_LO threshold. As mentioned in the Section 5.15 section, once VCCA reaches VSYS_LO, there is about 180 us delay before all the output rails are disabled simultaneously.
There are two scenarios to consider in the system-level design in the event of unexpected loss of power.