I've been working on a GPS tracker which is intended to run/idle on a battery for an extended length of time (2+ years). The tracker uses an accelerometer (LIS3DH) and remains in a sleep state until it is awoken due to movement. While the tracker is asleep, current levels need to remain as low as possible to help preserve the battery. The accelerometer is capable of running on 2-3uA in a sleep state but can only tolerate a voltage input of 1.7 - 3.6V. As I will be powering this from a single cell LiPo (3.7V+) I need to ensure that the accelerometer VCC doesn't exceed 3.6V.
Using either a SMPS or a linear regulator would achieve this but would consume too much current to be practical. I would like to know if I can use a diode's forward voltage drop to ensure that the input voltage isn't exceeded.
In a more conventional setting where a reasonable amount of current is being passed through the diode, I assume this would work. However, I am not certain 2-3uA will suffice. Is the voltage drop of a diode tied to the level of current passing through it?