Solutions for image rejection CMOS LNA

Author

Svelto, Francesco ; Montagna, G. ; Deantoni, S. ; Braschi, G. ; Castello, R.

Author_Institution

Dipt. di Ingegneria, Univ. di Bergamo, Dalmine, Italy

Volume

3

fYear

2000

fDate

2000

Firstpage

49

Abstract

This paper deals with the realization of a high image rejection (IR) CMOS LNA, tailored to DECT applications. Two topologies are proposed. The first one makes use of a Q-enhancement circuit and provides 15 dB IR with 300 MHz IF, 4.5 dB NF and -13 dBm IIP3. A notch filter loads the second LNA. The results are the following: 30 dB IR, 5.5 dB NF and -10 dBm IIP3. In both cases the frequency control is performed by means of an integrated MOS varactor. These circuits prove to be suitable for highly integrated CMOS receivers employing wideband IF architecture. At the expense of an almost double current consumption with respect to classical LNA, they provide enough image rejection to get rid of off-chip image rejection filters

Keywords

CMOS analogue integrated circuits; Q-factor; UHF amplifiers; UHF integrated circuits; cordless telephone systems; frequency control; integrated circuit noise; low-power electronics; notch filters; telephone sets; varactors; 1.88 GHz; 2.2 GHz; 300 MHz; 4.5 dB; 5.5 dB; DECT applications; Q-enhancement circuit; frequency control; highly integrated CMOS receivers; image rejection CMOS LNA; integrated MOS varactor; notch filter; wideband IF architecture; Active inductors; CMOS technology; Energy consumption; Frequency control; Noise figure; Noise measurement; Passive filters; RLC circuits; Tuning; Varactors;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 2000. Proceedings. ISCAS 2000 Geneva. The 2000 IEEE International Symposium on

Conference_Location

Geneva

Print_ISBN

0-7803-5482-6

Type

conf

DOI

10.1109/ISCAS.2000.855993

Filename

855993