As mentioned in this thread, I have a SAM R21 driving a piezo sounder element with complementary drive:
Obviously the above is just a prototype, but the client is getting field returns with excessive (~1mA when it should be ~3uA) current drain in standby.
One thing I've noticed is that there are "spikes" on the pins driving the piezo - CH2 (turquoise):
Zooming-in on a spike:
The supply is 3V; so 3.8V is quite an overshoot - and exceeds the "Absolute Maximum" in the datasheet.
So the "General Electronics" question is: is it possible/likely that this could be stressing the pin drivers, and leading (eventually) to the excess current ... ?
(after all that is the meaning of the "Absolute Maximum" ratings - isn't it?)
Has anyone seen such things causing problems elsewhere?