Broadband noise is a noise that appears at higher frequency compared to 1/f noise. The broadband noise is dominated by white noise as shown in Figure 8-8 . The broadband noise is measured by high-pass filtering the output of the REF80 and measuring the result on a spectrum analyzer as shown in Figure 8-7. The DC component of the REF80 is removed by using a high-pass filter and then amplified. When measuring broadband noise, it is not necessary to have high gain to achieve maximum bandwidth.

For noise sensitive designs, a low-pass filter can be used to reduce broadband noise output noise levels by removing the high frequency components. When designing a low-pass filter special care must be taken to make sure the output impedance of the filter does not degrade ac performance. This can occur in RC low-pass filters where a large series resistance can impact the load transients due to output current fluctuations.