nRF54L15-Tag minimum sleep current

[John0123456]

I'm in the early stages of building a Thread + CoAP low-power sensor and using the nRF54L15-Tag as a starting point. Using NCS, the lowest idle current I can get is 13 microamps, measured by supplying 3.0V at the CR2032 holder terminals. The nRF54L15 itself should be 3 or 4 microamps in this state, and it appears that the BMI270 should consume an unavoidable 4 microamps.

What is the minimum possible current consumption with the nRF54L15-Tag board?

[Carl Richard]

Hello John!

Thanks for reaching out. I've been exploring this issue today and from my testing the extra power consumption you are seeing probably originates from the antenna switch on the board.

I couldn't find any exact numbers on the expected leakage currents in the electrical specification, but each of the control lines on the device contributes with around 3-4 µA when HIGH from what I can see. 

As you may know the nRF54L15 tag has two antennas and the switch is to change between these. If this behavior is not needed in your application, one antenna and the switch can be omitted and this contribution to the current consumption will be gone.

Also: how is your tag connected with a debugger? I saw somewhat higher power consumption with the tag connected to the nRF54L15 debugger while measuring current consumption.

Best regards,
Carl Richard

[John0123456]

For a Thread node, maybe I should try setting one of the antenna switch control lines low to see how the current consumption is affected.

I'm using a measurement power supply connected to the contacts of the (empty) CR2032 holder. I haven't cut the solder bridge, and the Tag is not connected to the debugger or anything else.