I'm interested in using the undervoltage detection feature (in addition to the primary function) of this chip. This IC draws 6 uA (microamps), and accepts any VCC between 1.6V and 5.5V.
The undervoltage detection works like this: When VCC of this IC is below V_threshold, it will declare an undervoltage condition and set a LOW on its "Enable" Output Pin.
Now, the problem is this:
While the IC is available with multiple variants of V_threshold, the only available variants available are V_threshold = 2.0V, 2.9V, 3.1V, or 3.3V at most.
However, I wish to cut-off at threshold of 3.5V. I'm using a Lithium ion battery to supply the VCC pin of the IC; the battery's supply voltage would range from 4.1V (maximum) to 3.5V (my desired cutoff).
So, for the above situation in particular, which of the following options (or something else) might be the best solution for creating a smaller voltage locally for the IC's VCC, and why?
Choice 1) A diode? To create a constant drop between the battery source and the VCC pin of the IC.
or Choice 2) A resistive divider? To set a proportionally smaller voltage at the VCC pin of the IC.
or Choice 3) An LDO regulator? With 3.3V output, placed between the battery source and the VCC pin of the IC.