I'm designing an input buffer stage for a low voltage, noise sensitive application. These buffer stages consist of dual package OpAmps, with each individual OpAmp buffering the + or - input to a differential amplifier.
I'm comparing similar OpAmps for their noise specs, mainly their input noise voltage (spec given in nV / sqrt(Hz)), which I understand to be related to the white noise spectral density, and their 0.1 - 10Hz input voltage noise (spec given in nVp-p), which I understand is mainly related to 1/f noise. My application is low frequency, ~1-1kHz and will be effected by both of these figures.
My question is, is the noise from these sources common and directly related for the two OpAmps within the single package? In this case, will the noise then be removed by the differential measurement by the following amplifier stage?