Analyzing distortion contributions in a complex device model

Abstract

Purpose

The purpose of this paper is to propose a method to reduce the non-linear distortion of a transistor to its input and output ports to aid distortion contribution analysis (DCA). This is especially needed when the internal structure of a device model is complex.

Design/methodology/approach

The non-linear distortion generated by all non-linear sources inside a device model are reduced to transistor i/o ports by LMSE fitting techniques. Simulations of an LDMOS power transistor are used to compare the reduced distortion results with the actual non-linear sources.

Findings

It is shown, that device models where the current sources are split by intermediate nodes cause superficial results, when distortion contributions are calculated as a superposition of contributions from individual non-linear sources. The proposed iterative fitting technique works.

Research limitations/implications

Some non-quasistatic effects and the transfer functions from external terminals to internal controlling nodes are not covered.

Practical implications

The analysis is a step toward a generic non-linear distortion contribution simulation tool that would aid the designers to develop more linear analog circuits.

Originality/value

The concept of DCA itself is fairly new. This paper makes a step to represent the distortion sources in a canonical way.

Citation

Rahkonen, T. and P. Aikio, J. (2014), "Analyzing distortion contributions in a complex device model", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 33 No. 4, pp. 1264-1271. https://doi.org/10.1108/COMPEL-11-2012-0354