Noise is a central topic in analog circuit design, directly affecting how much information can be extracted from a measurement as well as the economy with which the required information can be obtained. Unfortunately, there is a large amount of confusion and misinformation regarding noise, which has the potential to cause underperformance, costly overdesign, or inefficient use of resources. This article from Analog Devices addresses 11 of the most persistent myths about noise analysis in analog designs.
Myth #1: Decreasing the Resistor Values in the Circuit Always Improves the Noise Performance It is a well-known relationship that noise voltage increases with higher resistor values according to the Johnson noise equation, erms = √4kTRB, where erms is the rms voltage noise, k is Boltzmann’s constant, T is temperature in Kelvin, R is the resistance, and B is the bandwidth. This leads many engineers to the conclusion that resistor values should be reduced in order to reduce the noise. Although this is often true, it cannot be assumed because there are specific examples where larger resistors improve the noise performance.
Learn about the other 10 most persistent myths about noise analysis in analog designs in this Analog Devices paper.
Read more here.
