nRF9160 max current draw

[Aaron]

I'm trying to find a battery for my application and I need to know the max (peak) current draw for the nRF9160. On page 63 of the user guide, the max is 435mA with the specs “extreme operating conditions” and “Ant VSWR3". When I use the online power profiler, the max I see is roughly 100mA (even with the 23dBm LTE setting). 

2 questions: 

What do the specs “extreme operating conditions” and “Ant VSWR3" mean? 

And why doesn't the online power profiler show this current draw? 

In order to determine the battery life I need to know the average current (which is shown on the power profiler) and the max peak, which says 435mA in the datasheet, but is not show on the power profiler. Any clarification would help. 

Thanks! 

[Håkon Alseth]

Hi,

 

What do the specs “extreme operating conditions” and “Ant VSWR3" mean? 

 It's the outer ends of the operating conditions.

VSWR3 = voltage standing wave ratio of 3. Ie. how well matched the antenna is at the given frequency.

And why doesn't the online power profiler show this current draw? 

When I use the online power profiler, the max I see is roughly 100mA (even with the 23dBm LTE setting). 

The power profiler shows averages (not peaks), as described in the bottom of the page:

https://devzone.nordicsemi.com/nordic/power/w/opp/3/online-power-profiler-for-lte

 

Kind regards,

Håkon 

[Aaron]

Thanks for the response. Do you have any info on the duration of the peak current pulse? i.e. Can I assume it will be a fraction of the tallest peak shown in the power profiler? For example, the RRC release looks to have the tallest peak (~100mA), can I assume it will be a fraction of that time period? Or what event does the peak occur? I'm trying to get an accurate power profile for our battery specification and supporting a 430mA pulse puts us into a different battery type depending on how long it happens. 

[Håkon Alseth]

Hi,

 

Aaron said:

Do you have any info on the duration of the peak current pulse? i.e. Can I assume it will be a fraction of the tallest peak shown in the power profiler?

In a overall scenario: This highly depends on the activity between the device and the cell tower.

W.r.t the specification, it is the peak within a tx subframe (1 ms). 

 

Aaron said:

For example, the RRC release looks to have the tallest peak (~100mA), can I assume it will be a fraction of that time period?

 That is defined with the lowest time period as well, so its peak is likely higher, as its a TX frame inside of this timeframe.

I would strongly recommend that you evaluate the current consumption profile of your product, as you will also get the current consumption of everything else on your board (if you have any external components / ICs) in a asynchronous way (think of accelerometers, gyros, LEDs, etc)

 

Kind regards,

Håkon