ZHCSG94L August 2013 – February 2019 TPS659038-Q1 , TPS659039-Q1
PRODUCTION DATA.
VCC1 is the supply for the analog input voltage of the device. This pin requires a 10-µF decoupling capacitor.
Texas Instruments recommends to always power down the TPS65903x-Q1 before removing power from VCC1. If the input voltage to the device is removed while the device is ACTIVE, the device will shut off when VCC1 reaches the VSYS_LO threshold. As mentioned in the Section 6.4.11 section, once VCC1 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.