Running nRF52833 at 1.8V versus 3.3V

[FCian]

I'm making a device that has a nRF52833 along with an IMU, SPI flash and an LED.  This device is running off a CR2032 battery and, of course, we're trying to stretch the battery life as long as possible.  The voltage drop for the LED is 2.2V or so, so I have boost on board and can boost to 3.3V.  My IMU can be powered at 1.8V and I can pick a memory chip that is either 3.3V or 1.8V.  So, I'm wondering, is it more energy efficient run the nRF52833 at 1.8V or use the external boost to 3.3V since I already have it on board.  I know there are a lot of factors, but in general.  I'm asking because I need to chose the memory to be 3.3V or 1.8V.  The memory chip and LED are the biggest power drains, so the plan is to limit them to as small as possible. 

Thank you,

ian

[Kenneth]

Hi,

I would think running on 1.8V should be the lowest power, simply because for instance the nRF52832 will in any case need to regulate down the supply voltage internally, so to avoid efficiency loss of first go up to 3.3V and the efficiency loss of going down in voltage again seems redundant. But I guess you would need to look at the efficiency loss of regulators for various use cases (e.g. sleep and active) if you want to churn the numbers. 

Kenneth