Current consumption of nRF54L15DK

RE: Current consumption of nRF54L15DK

Kazi Afroza Sultana — Thu, 12 Feb 2026 13:03:18 GMT

Hello,

''I will double check the peak level with oscilloscope as well, but I am waiting for lower sense resistor.''

Yes, that sounds like a good plan. We have an old blog (Current measurement guide: Introduction - nRF5x - Hardware design, test and measuring - Nordic DevZone) which describes about using a lower sense resistor and an oscilloscope with ≥200 kSa/s on the shunt to directly view the pulse shape and peak level.

''another reason why I was surprised with inrush spike, was because on nrf52840DK I did not observe any spike. Could you comment on this''

The principal of hysteric/refreshing are similar for both nRF52840 and nRF54L15. But regulator implementation, board decoupling differs. The capacitance on the output of the internal regulator is larger on the nRF54L15 (2.2uF) than nRF52840 (1uF). This causes the inrush current to be higher in the nRF54L15.

RE: Current consumption of nRF54L15DK

urban.gregorc — Tue, 10 Feb 2026 16:16:58 GMT

Hello Kazi,

thanks for the explanation. It makes sense.

I have doubled checked the average current. So for the 0dBm, 8Bytes and 30ms adv interval the average current is 138uA, which is a bit more than 121uA by Nordic's Online Power Profiler. I guess the reason is the peak measurement of inrush current. I will double check the peak level with oscilloscope as well, but I am waiting for lower sense resistor.

P.S. another reason why I was surprised with inrush spike, was because on nrf52840DK I did not observe any spike. Could you comment on this?

RE: Current consumption of nRF54L15DK

Kazi Afroza Sultana — Tue, 10 Feb 2026 12:36:08 GMT

Hello Urban,

A bit more explanation from expert in addition to my last comment.

The spike is the outcome of the inrush current to the DECD/A capacitors. When the system wakes up from idle, the internal voltage increases from 0.7V to 0.9V. This will cause an inrush current into the DECD/A capacitors. This is normal and how the regulator is designed to operate.

It is worth mentioning that the energy used to charge the capacitors, will be regained when the output voltage of the internal regulator drops down to 0.7V in idle mode, after the active period. The max current of the spike will depend on the internal resistance of the supply, and the total decoupling on VDD.

Inductance between the measuring tool and the VDD input, as well as changes in output impedance of the measuring tool, due to automatic range switching, may cause the spike to overshoot and look more dramatic than it really is.

RE: Current consumption of nRF54L15DK

Kazi Afroza Sultana — Tue, 10 Feb 2026 11:31:15 GMT

Hello Urban,

I don't think you need to do any hardware change. It seems expected behavior to see spike due to regulator's behavior. Have you measured the average current from the oscilloscope reading?