The formula from the referenced SE answer is oversimplification. If total noise in a given bandwidth is desired, one must **integrate** the noise over a bandwidth, and the spectral noise densities at, say, 10 Hz vs 100 kHz are different figures. You cannot just **multiply** the spectral noise density at 100 kHz by a square root of the bandwidth and have a total rms noise figure for this frequency range. The product gives only valid result for a flat PSD, i.e., for a white noise frequency distribution. Also, when applying the general formulas to DUTs, you should include all the circuit components and usage into your analysis. You can make an attempt at such research for the designated components: the datasheets you cited contain the graphs of spectral noise density vs. frequency. The Texas Instruments [Application Report AN-104 Noise Specs Confusing?][1] provides a detailed guide on all sorts of terms like signal-to-noise ratio, noise figure, noise factor, noise voltage, noise current, noise power, noise spectral density, noise per root Hertz, etc. [1]: https://www.ti.com/lit/an/snva515c/snva515c.pdf