Hello,
We're improving a battery-powered (CR2032) sensor tag based on an NRF52833 with a 868 MHz transceiver.
We want to use the nPM2100 PMIC and would like to optimize the design for maximum battery lifetime.
Load profile:
- Very low idle current ~4µA
- Current bursts when sensor active (3mA for 2ms) or transceiver active (every 5 minutes, see measurement below)
Questions:
- Optimal BOOST VOUT:
The lower the better? (PMIC in pass-through mode no additional current for active boost mode) - CVBAT sizing:
10 µF (reference design) + ? µ (according to https://docs.nordicsemi.com/bundle/nwp_058/page/WP/nwp_058/boost_input_output_capacitor.html)
However we have a different current profile than a BLE device.
Use 2 capacitors in parallel or is a sigle larger one enough? - CVINT sizing:
Is CVINT used when PMIC is in pass-through?
22 µF (reference design) or increase? - Any other design hints for improving battery life (e.g. capacitors on RF-chip, ...)
Any guidance would be much appreciated. Thanks!
Best regards
Mathias