A New Circuit Topology for the Realization of Very Low Noise, High Stability Voltage Sources

A new topology for the realization of high-stability very low noise voltage references is presented. The topology relies on a self-biasing circuit configuration based on a low-noise operational amplifier (OA). The series connection of a number of forward-biased low-noise diodes is used as an internal reference for generating any desired output voltage. The circuit may include a temperature stabilization system for obtaining very high stability coupled to very low noise. As an example, a 5-V reference with an output power spectral density of as low as 22 nV√Hz at 100 mHz, 7 nV√Hz at 1 Hz, and less than 6 nV√Hz for frequencies larger than 10 Hz can be obtained with a temperature stability better than 15 V/°C (less than 3 ppm/°C).