nRF54L15DK System_OFF and System_ON with RAM retained current measurement

[Muhammed]

As per nRF54L15 datasheet, system_off current at 3V VDD is 0.8uA. I am getting negative average current when i measuring System_OFF current consumption of nRF54L15 using nRF54L15DK board (VDD=3V) as below.

But when configure vdd=1.8V using nRF board configurator i'm getting ~0.9uA. 

Application : ncs\v3.1.1\zephyr\samples\boards\nordic\system_off

modified the application by adding CONFIG_APP_USE_RETAINED_MEM=n  in prj.conf .

i have followed the current measurement application notes.

Could you please help me with this? is there any configuration i missed?

[Muhammed]

Hi Simon,
Yes, we are still observing the negative current at 3.3V even after disabling both the VCOMs and the debugger.

Regards,
Muhammed

[Simonr]

Okay, can you confirm how you power the DK exactly? Where do you supply the 3.3V exactly, and do you have the firmware you're using for us to try reproducing this on our side?

Best regards,

Simon

[Muhammed]

Sure, please find the photo below. Powered through USB device and Power debugger is connected to VDDM current measurement header.

Board configurator:

configured the VDD to 3.3V  and disabled VCOMs and debugger.

Firmware: Loaded the board with example application, "system_off" (ncs\v3.1.1\zephyr\samples\boards\nordic\system_off)

Thanks,
Muhammed

[Simonr]

Hi

I tried to reproduce this on my end today. My setup is identical to yours except that I do measurements with the PPK2. I'm not able to see a negative current draw in any configuration on 1.8V, 2.5V or 3.3V. I have the same behavior on two boards, where it runs between 0.7-1.0µA in system OFF mode on two different DKs. Both one v0.9.2 and a v1.0.0 on my end. 

The only component I'm unfamiliar with in your setup is the Power Debugger. I assume it is the one from Microchip? https://www.microchip.com/en-us/development-tool/atpowerdebugger 

I see that the A channel has both a high and low range, so can you confirm it is not "locked" in the high range where t has only ~3µA resolution? I also see that the low-range resolution is only specified betweeen 1mA  1µA, so below 1µA I guess you're not guaranteed to get accurate measurements. I don't want to be the guy blaming your hardware, but since I'm not able to reproduce it on my end I don't see many other reasons for this. 

Best regards,

Simon

[Muhammed]

we measured with keysight DMM, got 0.8uA for the system_off mode.  Thanks for the support and suggestions.

Is there any example application available for measuring remaining configurations in sleep modes like Ion_Idle1 as below:

Thanks and regards,
Muhammed