Hello,
I was using the TPS613221A (3.3V Vout Version) for a wearable device, using as a power input a single AA/AAA Battery Cell (1.5V) and also 2 AA/AAA Battery Cells in Series (3V), we have observed that when the batteries are fully discharged and the voltage goes below of 0.9V the regulators start to draw currents in excess of 500mA at the Input acting as a short circuit (this happen most often when we use a single AA/AAA cell).
this event is no documented in the datasheet.
What can cause this?
there is a way to prevent it?