nRF52840 regulators

[Daniel]

Hi, 

My team is building a wearable application similar to a smartwatch.

Our system requires two main operating voltages. 1V8 and 3V3. I was thinking that we would use a PMIC to regulate these two voltages from a battery supply. We are trying to maximize battery life on this application.

I was wondering if I could use the on-chip REG0 to regulate one of my voltages. Can I do this? Is it more efficient than using a PMIC? Which voltage should be regulated? Right now, I am thinking that I regulate the battery myself, supply 3V3 to the nRF52840 and let it regulate down to 1V8.

Please let me know,

D

[Daniel]

Decided to go with a PMIC to supply both rails.

I found a note in the errata for the nRF52840 describing how the first stage DC-DC regulator does not work. This would force me to use the LDO to drop from 3.3V to 1.8V. Horribly inefficient.