nRF9160 TX current duty cycle (configurable?)

RE: nRF9160 TX current duty cycle (configurable?)

ketiljo — Thu, 07 Jan 2021 15:22:09 GMT

Not unless the network lets you do that. All timing is decided by the base station.

RE: nRF9160 TX current duty cycle (configurable?)

alcornb — Tue, 05 Jan 2021 15:54:52 GMT

Hi Ketiljo,

Phew! Thanks for the response. Is there any way to add a rest time between the 32ms cycles? This seems to restart immediately from what I can tell.

RE: nRF9160 TX current duty cycle (configurable?)

ketiljo — Tue, 05 Jan 2021 14:32:38 GMT

1. The duty cycle will be 3 ms on and 5 ms off for a duration of max 32 ms.

2. There's a difference between gen1 and gen2 of the nRF9160. The current is lower on gen2 due to more efficient regulators. 6-700 mA is too high, sorry for that. For gen1, peak current is ~525 mA for the modem. This is down by up to 19% on gen2,depending on the band, see https://infocenter.nordicsemi.com/pdf/pcn_134_v1.0.1.pdf

For new design, use the numbers for gen2 in the current PS

RE: nRF9160 TX current duty cycle (configurable?)

alcornb — Mon, 04 Jan 2021 19:36:10 GMT

Hi Ketiljo,

Thanks for your reply. I can't design the power supply based on the typical case, it needs to be worst case. To clarify, you're saying:

1. Worst case duty cycle is 32ms on and 5ms off?

2. Worst case peak current draw is 6-700mA @ 3.6V? That doesn't align with the spec for the 9160. The highest current consumption stated in the datasheet is 390 mA @ 3.5V. Are you saying the highest current consumption is higher than that which is spec'ed in the datasheet? What am I missing?

RE: nRF9160 TX current duty cycle (configurable?)

ketiljo — Mon, 04 Jan 2021 12:43:03 GMT

1. Typical CAT-M1 TX case would be 1-3ms TX and 5ms minimum gap before next 1-3ms TX. In cell edge areas the TX periods can be significantly longer - worst case up to 32 ms. The current draw will vary with the distance to the base station. So expect a worst case peak current draw of 6-700 mA.

2. No, this is solely decided by the network

3. Not other than that your battery and capacitor combination must be able to supply the current needed by the modem. The battery selection is key to make a robust system. Also check the temperature spec. of the battery.