A magnetic field sensor includes a magnetic field sensing element to generate a magnetic field signal indicative of a sensed magnetic field, a modulator to modulate the magnetic field signal at a chopping frequency, a front end amplifier coupled to receive the magnetic field signal and generate an amplified signal, and a demodulator configured to demodulate the amplified signal at the chopping frequency. The sensor further includes a low pass filter to process the amplified signal and generate a low pass filtered signal and a Schmitt trigger circuit. The Schmitt trigger circuit includes a comparator having a first input coupled to receive the low pass filtered signal, a second input coupled to receive a reference signal, and an output at which a comparator output signal is provided. The comparator is configured to perform a plurality of comparisons within a chopping time period that is the inverse of the chopping frequency.