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Frequently Asked Question

What is the noise performance of digital potentiometers?

We usually just specify the thermal noise (Johnson Noise) which is eN = sqrt(4*k*R*T*BW) where k is Boltzman's constant, k=1.38E-23, R is resistance, T is temperature in Kelvin and BW is bandwidth. To reduce noise, one should reduce R in the system and/or the operating BW. Thermal noise is believed to be a major noise component and good for 1st order approximation. The total noise in the system is usually slightly higher.