When using a hall effect sensor like this one, naturally, it will be pretty close to a rapidly changing magnetic field. This means that the analog signal line coming out of the sensor will also be close to a rapidly changing magnetic field. I'm concerned about shielding this analog signal from the very field that the hall effect sensor is trying to measure. According to my back-of-the-envelope calcs, I shouldn't have to worry about this... can someone confirm my calculations?
I know that Lenz's Law tells us that induced voltage due to a changing B-Field is given by
and of course
Given the strength of the magnets in my physical setup and their position relative to my loop, I expect a maximum dB/dt of about 10Tesla / second. My pcb is the standard 0.1524mm trace/space, so I could conservatively have the loop of "analog signal + return path" be on the order of 10^-5 square meters.
All of this suggests that even with a rapidly moving magnetic field, I will have less than 1 milliVolt of noise in my (very delicate) analog signal.
Is my analysis sane, or is EMI protection a problem when measuring a rapidly changing B-field with a hall effect sensor?