nRF52833: ~60 mA current spikes during light sleep on PPK2

[S149_2025]

Hi Nordic Team,

I’m observing ~60 mA (or higher) current spikes while measuring with Power Profiler Kit II (PPK2) on an nRF52833. Outside of these spikes the system sits around ~24 µA average (light sleep/idle). If we can identify and eliminate the spikes, the average will drop significantly.

• Battery/Power: 200 mAh Li‑Po (device normally battery‑powered)
• SoC: nRF52833 (custom board)
• SDK/OS: [Zephyr / nRF Connect SDK v3.1.0]
• Tooling: PPK2 
• Firmware state during spikes: system in “light sleep” with advertising interval of min:960ms - max:1000ms

I’ve attached:

1. PPK2 capture screenshot showing ~60 mA spike
    
2. PPK2 CSV log around the spike window ppk-20260323T083218.csv
3. Active .config file for the build .config

[Kenneth]

Hello,

If you want to share PPK2 plots with us, please save and share the .ppk2 file (not .csv format).

That said, when in idle the nRF52833 is operating in refresh mode, where it periodically refresh the decoupling capacitor on it's regulator, this refresh mode can cause high (but short) current pulses. Unfortunately as the PPK2 change measurement range during these short pulses it may show higher current than it actually is. https://docs.nordicsemi.com/bundle/ug_ppk2/page/UG/ppk/ppk_measure_resolution.html 

There is no good workaround to this, other than add much more decoupling on VDD to reduce the refresh spikes.

Kenneth