Title :
CMOS active-LC bandpass filters with coupled-inductor Q-enhancement and center frequency tuning
Author :
Bantas, Sotiris ; Koutsoyannopoulos, Yorgos
Author_Institution :
Sch. of Electr. & Comput. Eng., Nat. Tech. Univ. of Athens, Greece
fDate :
2/1/2004 12:00:00 AM
Abstract :
A novel CMOS circuit for obtaining a bandpass response from a triple-coupled-inductor arrangement is presented, featuring Q-enhancement and center frequency tuning by means of vector-modulating a current flowing through one of the coupled inductors. A 0.35-μm CMOS LC filter prototype employing the technique has been fabricated and exhibits a center frequency tuning range of 11% around 1 GHz and Q values up to 180. The input 1-dB compression point is -13 dBm with Q set to 20 and a power consumption of 12.2 mW. Additionally, an input impedance matching scheme around a spiral transformer is presented, which tracks the center frequency of the filter. The active-LC approach can be applied to higher order filter responses and find applications in tunable building blocks for agile RF front ends and multistandard radios.
Keywords :
CMOS integrated circuits; Q-factor; active filters; band-pass filters; inductors; modulators; CMOS LC filter; CMOS active-LC bandpass filters; CMOS circuit; Q enhancement; Q value; RF front ends; bandpass response; center frequency tuning; coupled inductors; coupled-inductor Q-enhancement; current flow; input impedance matching; integrated filters; integrated inductors; multi-standard radios; power consumption; spiral transformer; triple-coupled-inductor arrangement; vector-modulation; Band pass filters; Circuit optimization; Coupling circuits; Energy consumption; Frequency; Impedance matching; Inductors; Prototypes; Spirals; Tuning;
Journal_Title :
Circuits and Systems II: Express Briefs, IEEE Transactions on
DOI :
10.1109/TCSII.2003.821521
