A simple technique to evaluate the noise spectral density in operational amplifier based circuits using the adjoint network theory

Author

Vasudevan, V.

Author_Institution

Dept. of Electr. Eng., Indian Inst. of Technol.-Madras, Chennai, India

Volume

51

Issue

11

fYear

2004

Firstpage

2175

Lastpage

2178

Abstract

We use the adjoint network theory to get quick estimates of the noise contributed by various elements in linear time-invariant opamp based circuits. The noisy operational amplifier is represented using a or with an input referred noise voltage and current source. The adjoint model for this representation is derived. This makes the noise analysis of operational amplifier based circuits very simple and the contribution of the operational amplifiers to the output noise can be obtained very often by inspection. The method is applicable to amplifiers, active RC and MOSFET-C filters. Examples of circuits analyzed include the universal active filter and gyrator topologies.

Keywords

RC circuits; active filters; active networks; circuit noise; operational amplifiers; spectral analysis; MOSFET-C filters; active RC filters; adjoint network theory; gyrator topologies; noise analysis; noise spectral density; operational amplifier; or; universal active filter; Active filters; Active noise reduction; Circuit noise; Circuit topology; Inspection; Intelligent networks; Operational amplifiers; Resistors; Transfer functions; Voltage; 65; Adjoint theory; noise; operational amplifier;

fLanguage

English

Journal_Title

Circuits and Systems I: Regular Papers, IEEE Transactions on

Publisher

ieee

ISSN

1549-8328

Type

jour

DOI

10.1109/TCSI.2004.836858

Filename

1356149