nRF9151 udp sample 5µA current consumption

[samuel4]

Hi

I have tried to reproduce the 2.7µA current consumption stated in the datasheet. This webinar shows that the UDP sample reaches 2.7µA on the nRF9160 evaluation kit. However, on my evaluation kit I get 5µA average consumption. I can open the sim current jumper without any change in current, so the sim card should be shut off.

Do you have any ideas what could cause the additional ~2.3µA?

Kind regards
Samuel

[Charlie]

Hi Samuel,

Is your evaluation kit a nRF9151DK?

How many divices have you measured?

Best regards,

Charlie

[samuel4]

Hi Charlie

Yes, it is an nRF9151DK. I have tested one evaluation kit, only. I can test 2 more kits more tests on monday.

Kind regards

Samuel

[Charlie]

Hi Samuel,

2.7µA is the typical vaule of Power Class 3 modem current consumption as stated in the datasheet. However, this value may vary depending on chip variations, measurement equipment/methods, and network conditions.

Using a PPK2 in Source Meter mode to power the chips, I measured PSM floor current of 3.26 µA on one nRF9151DK v0.9.10 board, and 2.92uA on one nRF9161DK v0.9.1 board.

Best regards,

Charlie

[samuel4]

Hi Charlie

Thank you for your measurements. I could verify 2.8µA sleep current with an nRF9161dk and after upgrading the SDK to the latest version the sleep current on the nRF9151 dropped to 3.3µA without SIM card inserted. Currently, I have some issues with enterning PSM - I am investigating on that.

I think the main issue was that the SDK got a work arround recently that activated the buck converter. The consumption might have been higher with LDO operation.

Kind regards

Samuel

[samuel4]

Hi Charlie

I have tested two nRF9151 in PSM:

- 3.17µA

- 2.85µA

I used a DMM6500 for current measurement. Since the modem is in PSM I guess network conditions should not matter. Probably, the deviations come from chip variations. Is this a known issue?

Kind regards

Samuel

[Charlie]

Hi Samuel,

Thanks for sharing. I will inquiry our chip design team about this topic.

Just want to confirm, are you still testing nRF9151DKs? If yes, can you share their HW version?

Best regards,

Charlie

[samuel4]

Hi Charlie

Thanks for investigating - I am curious about the answer of your chip design team.

We have three nRF9151dk with version 0.9.0. I have tested the third kit, which reaches 2.84µA. I will try to get more recent evaluation kits and do more tests.

Kind regards

Samuel

[Charlie]

Hi Samuel,

According to the chip designer, the previously reported values are within the “normal” variation range. For early A0A samples of the nRF9151, PSM floor current variations of up to 4.5 µA may occur in worst-case scenarios.

Later versions of the nRF9151 exhibit less variation, and the worst-case scenarios seen in early samples should no longer exist. However, some variation above the typical 2.7 µA value specified in the datasheet can still be observed. It is important to note that unit-to-unit variation in this value is expected and inherent.

Best regards,

Charlie