Teensy is nowhere close to most power efficient options out there. A power efficient arm can be running on micro or even nanoamps in sleep mode. It will of cour

Teensy is nowhere close to most power efficient options out there. A power efficient arm can be running on micro or even nanoamps in sleep mode. It will of course depend on the rest of the circuit surrounding MCU. I use STM L4 for my projects. https://www.st.com/resource/en/product_training/STM32L4_System_Power.pdf https://www.st.com/resource/en/product_training/STM32L4_Syst... On page 4 it says down to 30nA with I/O wakeup, 350nA with 32kB memory retained.