MCU alternatives

Nicenano v2

Supermini

 Released by Nologo, first known as supermini, then renamed to nrf52840.  There is workaround suggested by Joric.

It has higher leak than nin/nrfmicro, deep sleep uses 700uA with VCC off. The nin uses about 20uA. Desoldering the resistor brings quiescent current from over 700uA to under 20uA. Desolder resistor on the picture and/or replace it with 10M. Why the resistor leaks? Because when VCC cut-off is enabled and power control pin is set to GND (zero) it pulls down VDDH to GND. It is about 3.6V/5.6K ~ 0.650 mA just from this resistor alone. It's confirmed to work fine without the resistor (it's there to prevent floating and enable LDO by default when the power control pin is uninitialized). 10M resistor works too (lower current, same voltage) it only affects gate saturation time (t=R*C), which is negligent (picoseconds), leak will be 3.6V/10M ~ 0.36 uA.