SNAS781E October 2020 – July 2022 REF70
1/f noise, also known as flicker noise, is a low frequency noise that affects the device output voltage which can affect precision measurements in ADCs. This noise increases proportionally with output voltage and operating temperature. It is measured by filtering the output from 0.1-Hz to 10-Hz. Since the 1/f noise is an extremely low value, the frequency of interest needs to be amplified and band-pass filtered. This is done by using a high-pass filter to block the DC voltage. The resulting noise is then amplified by a gain of 1000. The bandpass filter is created by a series of high-pass and low-pass filter that adds additional gain to make it more visible on a oscilloscope as shown in Figure 8-6. 1/f noise must be tested in a Faraday cage enclosure to block environmental noise.
Typical 1/f noise (0.1-Hz to 10-Hz) distribution can be seen in Figure 8-7.