Excess current noise in amplifiers with switched input

Author

Drung, Dietmar ; Krause, Christoph

Author_Institution

Phys.-Tech. Bundesanstalt, Berlin, Germany

fYear

2014

fDate

24-29 Aug. 2014

Firstpage

556

Lastpage

557

Abstract

A basic model for excess current noise in amplifiers with switched input is presented. Thermal noise in the input switches causes charge fluctuations in the amplifier input capacitance with a bandwidth much higher than the switching frequency. This wideband charge noise is undersampled by the switching process, leading to excess current noise with a spectral density proportional to temperature, capacitance and switching frequency. The model was verified using a test chopper operated at room temperature and liquid Nitrogen (77 K). Good agreement between theory and experiment was found.

Keywords

amplifiers; choppers (circuits); circuit noise; electric charge; switches; thermal noise; amplifier; capacitance frequency; charge fluctuation; current noise; liquid nitrogen; spectral density; switched input; switching frequency; temperature 293 K to 298 K; temperature 77 K; test chopper; thermal noise; undersampled wideband charge noise; Capacitance; Choppers (circuits); Noise; Noise measurement; Switches; Switching frequency; Temperature measurement; Chopper amplifier; current noise; noise model; switched input; thermal noise;

fLanguage

English

Publisher

ieee

Conference_Titel

Precision Electromagnetic Measurements (CPEM 2014), 2014 Conference on

Conference_Location

Rio de Janeiro

ISSN

0589-1485

Print_ISBN

978-1-4799-5205-2

Type

conf

DOI

10.1109/CPEM.2014.6898506

Filename

6898506