Calculating voltage monitor positive and negative threshold?
The specifications are pretty clear, the TPS389001 device ("adjustable" variant) will DEASSERT reset pin (pins go HIGH) if the voltage on pin "SENSE" reaches 1.157 V, and will assert RESET if the voltage will go below 1.150 V. This is how this kind of devices generally operate.

Therefore, if you have the 27k/47k voltage divider on the SENSE pin, the -RESET pin will go high if Vmon reaches 1.157*(27+47)/47 = 1.82 V (aka positive threshold), and will assert RESET pin LOW if the Vmon voltage drops below 1.81 V (aka negative threshold). Obviously both thresholds are positive relative to the common ground pin. This is a very sensitive voltage monitor!