Title :
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
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;
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
DOI :
10.1109/ISCAS.2000.855993
