Re: [EE] measuring the magnetic field from a small trace carrying a < 50uA load?

Is the following what you mean?

It might be possible to power the device off every few seconds, and then
after 10 milliseconds of the MCU running (10mA) and setting external
devices on serial buses to low power mode, the board could go into low
power mode drawing ~100uA.

This would expose a transition from 100uA down to 0uA once every few
seconds. But that is not very frequently. I suspect the cycle would have to
be slow enough to keep the activity of the MCU booting up from swamping the
signal.

-- 
Jason White