I recently started using the otii and I use it a lot, it gives me great insight in the current consumption of my electronics.
I have a problem with measuring the current from a battery powered wireless device that has an onboard booster (MAX17224ELT+) to boost the voltage from 2xAA alkaline (2-3V) to 3.3V. Sometimes, 1 out of 5-10 times, when I turn on the power switch of the otii (set to 3.0V and 2A over current protection) the current immediately starts with a baseline of 50mA and on top of that is the normal current current profile of the device (MCU). The otii is powered from a benchtop power supply (7V 3A) on the DC barrel jack on the back side. When I power my device directly from the benchtop power supply, I don’t get the 50mA baseline current. I am not sure where exactly is the problem. I can hardly believe it’s the microcontroller or other circuits on my board. I suspect the booster is the problem but only when connected to the otii. Inrush current is less than 180mA.
Have you seen similar problems before? Could it be series resistance in the power supply of the otii? Or maybe some interaction between otii power supply and my booster? Does the otii have a switching power supply? Or an LDO? Can I see the power supply circuit? Should I use thicker or more solid power supplies cables? Should I add filters or a LDO to the otii power supply?