I have a uC that works with 1.8V up to 3.3V. Current consumption is at about 20uA in sleep mode and about 12 mA in active state. The uC will enter active state for about 100 ms every minute.
So I am trying to power this from a Vishay super cap: 15F at 2.8 volts with an ESR of 1.2O at 1kHz.
Math says I can pull about 4.10 mA from this cap before its voltage drops to 1.8 volts, at which point the micro will shut down.
So.. the question: am I missing something? Should I add a small electrolytic between the super cap and the micro? A small zener to limit eventual (possible?) spikes in voltage? Should I add a buck boost converter to get a bit more out of the capacitor?
Also.. if I disable brownout detection on the microcontroller, maybe I can pull something like 10% more charge from the capacitor? I can implement error checking in case the micro outputs gibberish, which usually happens in low voltage scenarios with brownout detection disabled.