SYSTEMON vs SYSTEMOFF sleep

RE: SYSTEMON vs SYSTEMOFF sleep

Nikollao — Tue, 14 Oct 2025 07:25:33 GMT

Thanks.

RE: SYSTEMON vs SYSTEMOFF sleep

Vidar Berg — Tue, 14 Oct 2025 05:49:35 GMT

We specify the system run current with the CPU active, the startup time before the first instruction is executed on wake-up, etc. in the datasheet, but this alone isn't sufficient to make any estimates how much energy your device will consume as we don't know what the FW needs to do on startup before it's ready to perform tasks (record data for example). It's best to measure the startup current using a PPK2 or similar.

RE: SYSTEMON vs SYSTEMOFF sleep

Nikollao — Mon, 13 Oct 2025 15:58:01 GMT

Does Nordic provide any information how much energy the NRF54L15 uses during power up etc?

RE: SYSTEMON vs SYSTEMOFF sleep

Vidar Berg — Mon, 13 Oct 2025 12:34:04 GMT

Yes, that would make sense if you’re going to record data once every hour and don’t need any BLE connectivity in between. The cost of wakeup will depend on your application boot validation mechanisms in the bootloader, scatterloading, driver initialization, etc). I'm afraid my best suggestion is to profile this with your FW and HW.

RE: SYSTEMON vs SYSTEMOFF sleep

Nikollao — Mon, 13 Oct 2025 11:58:25 GMT

If I have a period eg record data 1 every hour it would make sense to use systemoff. My question is, power-wise what period would systemoff make sense compared to wfi? 1 second, 5 seconds, 1 minute?

RE: SYSTEMON vs SYSTEMOFF sleep

Vidar Berg — Mon, 13 Oct 2025 11:01:53 GMT

Hello,

Waking up from System OFF will trigger a System Reset, so even though you could likely achieve a lower average current for longer intervals, it’s not a viable option for most types of applications to enter system OFF periodically.

Best regards,

Vidar