NRF54L15-DK sleep current problem

[secondbest]

Hello Nordic team,

I bought newly announced NRF54L15-DK board. Its version is v0.9.1. I am using NCS v2.8.0. I tried to test sleep current via nrf52840-dk and nrf54l15-dk. When I compile my sleep_test project for nrf52840-dk, I am getting following result with 3V supply voltage.

The result seems okay to me for nrf52840-dk. However, if I use 3V supply voltage for nrf54l15-dk, I am getting following strange sleep average current.

After that, I tried to use 2.5V supply voltage with nrf54l15-dk and I got following idle current results. Strangely, I am seeing current spikes at every 4 seconds. 

I watched Nordic's demo on YouTube and I feel there is no this type of ticks on this demo. I wanna learn that how can I use 3V supply voltage and How can I solve this sleep issue?

Thanks. 

[Simonr]

Hi again

So, internally in the SoC, the nRF54L15 low-power domain (always on domain which can wake the rest of the system from System OFF mode) draws energy form the DECD capacitor. So periodically, VDD will draw some power to charge up this capacitor again, as the capacitor will charge and discharge between 0.7V and 0.9V.

Best regards,

Simon

[secondbest]

Thanks for the response. Shortly, you are saying that If supply voltage is 3V, 6uA idle current is normal.

[Simonr]

Hi, so in system off you should be able to get quite a bit of lower current, and I'm guessing this relates to RAM retention being enabled in your application. As opposed to the nRF52 series, RAM is retained by default in system OFF. It's safe to turn off RAM retention by setting both RET registers to 0 in order to disable RAM retention in system OFF mode. https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/memconf.html#ariaid-title4 

You can also try this hex and see if you get the specified 0.6uA?nrf54l15_xxaa_application.hex

Best regard,

Simon

[pawpec]

 Simonr Could you share your source code for "nrf54l15_xxaa_application.hex", please? I can't get nRF54L15 to go below 120uA current consumption using sys_poweroff but with you hex it drops down to 0.8uA  Not sure what I'm doing wrong...