Power Supply Design Guidelines for nRF9151 Modem

[Oleg-AgamControl]

We are developing a new board based on the NRF9151 and would appreciate some guidance regarding the power supply design for the modem.

Specifically, we’re looking for documentation or recommendations that cover:

• What is the optimal (from the point of view of minimizing energy consumption) supply voltage for the modem?

• What is the typical (nominal) current consumption over time?

• What is the peak current consumption and for how long can it last?

• Are there recommendations for capacitors to place near the modem to stabilize power during peak consumption?

[ketiljo]

What is the optimal (from the point of view of minimizing energy consumption) supply voltage for the modem?

The DCDC converter is most efficient at 3.7 V

What is the typical (nominal) current consumption over time?

You can simulate this here:  https://devzone.nordicsemi.com/power/w/opp/3/online-power-profiler-for-lte

What is the peak current consumption and for how long can it last?

You can find the current draw of the modem here: https://docs.nordicsemi.com/bundle/ps_nrf9151/page/_tmp/alta.nRF9151/autodita/APPLICATION.CURRENT/parameters.id_current_modem_pc_3.html

Peak current in extreme conditions, +85 degrees and VBAT = 3.0 V can be as high as 430 mA (class 3).

For NB1, an active TX period can be 32 ms cell edge areas.

Are there recommendations for capacitors to place near the modem to stabilize power during peak consumption?

You can not rely on supercaps or other large caps to compensate for a battery with low current delivery, the power supply must be able to handle the peak current. The reference design has a 47 µF cap on the VBAT pin.