How do you measure real current on your module?

Hi There!
How do you measure real current consumption from this module? Im trying to measure mine but I can’t go as low as uA range in my oscilloscope. (Rigol DS1052E)
I mean, I use a 0R22 shunt resistor in series with the battery. So when I measure 4-5mV (LP mode off), this means 15-20 mA, which is expected
Then I switch LP=1 and then I see voltage get down to ~1mv. This means 4-5mA, which doesn’t make sense. But then I disconnect the power from the module and I still get readings on my oscilloscope around 0.8–1.2mv!! WHY? I don’t know. but I actually touch the probe tip with the ground test lead and I still get these values on screen. I tried an auto-recalibration in the TOOLS menu but nothing changed.

I could use a larger shunt like 5Ohm so the read voltage would be 25 times bigger, but the TX/RX spikes during UWB communication would lead to a large voltage drop in this resistor that the module wouldn’t probably stand it.

Any other way to achieve valid readings of uA currents??

Thank you!

If you are hitting issues due to your test equipments noise level then use better test equipment. :slight_smile:

If you can keep the system in lower power mode for a long time then use a nice large series resistor but short it out while the system starts up. Once it’s in low power mode remove the short circuit and make your measurements. Not a practical solution for going in and out of low power but OK for a one off measurement.

Well I’m trying to measure the power consumption between TX/RX spikes, those would happen at a rate (with our current configuration) of once a second, so I can’t really move much stuff and resistors between spike and spike. I was told to build an amplifier with a LNA IC in order to keep the low ohm resistor shunt but get amplified readings 100 times larger with the amplifier. Spikes would get out of bounds but I don’t care for those, I do care for the deep sleep time consumption