Design of a low-distortion 22-kHz fifth-order Bessel filter

Author

Moon, Un-Ku ; Song, Bang-Sup

Author_Institution

Coordinated Sci. Lab., Illinois Univ., Urbana, IL, USA

Volume

28

Issue

12

fYear

1993

fDate

12/1/1993 12:00:00 AM

Firstpage

1254

Lastpage

1264

Abstract

A linearity improvement technique employing passive resistors and current-steering MOS transistors as a variable resistance element is proposed to implement a low-distortion filter in CMOS technology. This proposed implementation relies on the linearity of the passive resistors and the tunability of the current-steering MOS transistors operating in the triode region to overcome the limited linearity performance in continuous-time electronically tunable filters. By using the existing systematic feedback loops in the active filters and placing the nonlinear elements inside the feedback, the distortion resulting from the nonlinear devices is greatly reduced by the filter loop gain. A 22-kHz fifth-order Bessel filter, its dynamic range optimized by applying Karmarkar´s rescaling algorithm and self-tuned with a switched-capacitor reference resistor, demonstrates better than -90-dB THD with a 2-kHz, 4-V_pp signal in 5-V 2-μm CMOS

Keywords

CMOS integrated circuits; active filters; feedback; linear integrated circuits; linearisation techniques; tuning; 2 micron; 22 kHz; CMOS technology; current-steering MOS transistors; feedback loops; fifth-order Bessel filter; linearity improvement technique; low-distortion filter; passive resistors; rescaling algorithm; self-tuned type; switched-capacitor reference resistor; triode region; tunability; variable resistance element; Active filters; CMOS technology; Feedback loop; Linearity; MOSFETs; Moon; Nonlinear filters; Passive filters; Resistors; Tunable circuits and devices;

fLanguage

English

Journal_Title

Solid-State Circuits, IEEE Journal of

Publisher

ieee

ISSN

0018-9200

Type

jour

DOI

10.1109/4.261999

Filename

261999