Design Optimization Methodology of CMOS Active Mixers for Multi-Standard Receivers

B.P. 3038 Sfax Tunisia. (e-mail: [email protected]). F. Touati is with Sultan Qaboos University, P.O. Box 33, Muscat 123, Oman. (phone: 968-24142535; fax: 968-24413454; e-mail: touatif@ squ.edu.om). M. Loulou is with the national National School Of Engineering of Sfax, B.P. 3038 Sfax Tunisia. (e-mail: [email protected]). Abstract—A design flow of multi-standard down-conversion CMOS mixers for three modern standards: Global System Mobile, Digital Enhanced Cordless Telephone and Universal Mobile Telecommunication Systems is presented. Three active mixer’s structures are studied. The first is based on the Gilbert cell which gives a tolerable noise figure and linearity with a low conversion gain. The second and third structures use the current bleeding and charge injection techniques in order to increase the conversion gain. An improvement of about 2 dB of the conversion gain is achieved without a considerable degradation of the other characteristics. The models used for noise figure, conversion gain and IIP3 used are studied. This study describes the nature of trade-offs inherent in such structures and gives insights that help in identifying which structure is better for given conditions.