Best Low-Power Microcontrollers for Battery-Powered IoT Projects

There's no one-size-fits-all here.

Compare some applications:

1) a device that tracks multiple interactions between individuals to establish contact patterns and associations ( a bit like Covid contact tracking) so it must transmit a message every few seconds and receive messages with sub 1ms latency.

2) a remote water treatment monitoring station which must gather data continuously and send messages over  a long range perhaps once per hour or less and will receive messages at even longer intervals.

3) an air conditioning sensor which must transmit a few bytes of data at approx 5 minute intervals and has no need to receive data at all, but needs a 10 year battery life.

4) a shelf edge label which must receive data every few days, cost almost nothing and have a 10 year life.

All are low power applications but with completely different requirements.

There is no best processor or SOC that would be good in all these instances.

To get useful advice you need to provide more detail about the application.

To add to Shabaz's point about idle current - wild claims are made about chip idle currents but before you worry too much between 100nA and 10uA, check out the leakage current of any capacitors you might consider placing across the power rails and the battery's response to sudden changes of current.

There is an interesting article here:

https://www.ganssle.com/reports/ultra-low-power-design.html

I don't agree with every word of it but reading and understanding it will give you a good start.

MK

There's no one-size-fits-all here.

Compare some applications:

1) a device that tracks multiple interactions between individuals to establish contact patterns and associations ( a bit like Covid contact tracking) so it must transmit a message every few seconds and receive messages with sub 1ms latency.

2) a remote water treatment monitoring station which must gather data continuously and send messages over  a long range perhaps once per hour or less and will receive messages at even longer intervals.

3) an air conditioning sensor which must transmit a few bytes of data at approx 5 minute intervals and has no need to receive data at all, but needs a 10 year battery life.

4) a shelf edge label which must receive data every few days, cost almost nothing and have a 10 year life.

All are low power applications but with completely different requirements.

There is no best processor or SOC that would be good in all these instances.

To get useful advice you need to provide more detail about the application.

To add to Shabaz's point about idle current - wild claims are made about chip idle currents but before you worry too much between 100nA and 10uA, check out the leakage current of any capacitors you might consider placing across the power rails and the battery's response to sudden changes of current.

There is an interesting article here:

https://www.ganssle.com/reports/ultra-low-power-design.html

I don't agree with every word of it but reading and understanding it will give you a good start.

MK