A 1GHz CMOS variable gain amplifier with 70dB linear-in-magnitude controlled gain range for UWB systems

  • Authors:

  • Jia Cheng;Fengyi Huang;Yang Gao;Lianhong Wu;Yu Tian

  • Affiliations:

  • Institute of RF and Opto-Electronic Integrated Circuits, Department of Radio Engineering, Southeast University, Nanjing, China;Institute of RF and Opto-Electronic Integrated Circuits, Department of Radio Engineering, Southeast University, Nanjing, China;Institute of RF and Opto-Electronic Integrated Circuits, Department of Radio Engineering, Southeast University, Nanjing, China;Institute of RF and Opto-Electronic Integrated Circuits, Department of Radio Engineering, Southeast University, Nanjing, China;Institute of RF and Opto-Electronic Integrated Circuits, Department of Radio Engineering, Southeast University, Nanjing, China

  • Venue:
  • APCC'09 Proceedings of the 15th Asia-Pacific conference on Communications
  • Year:
  • 2009

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Abstract

This paper describes a design of an inductorless variable gain amplifier (VGA) for UWB systems in a standard digital 0.18µm CMOS technology. The VGA is implemented using four-stage modified Cherry-Hopper amplifier, and by changing the value of the feedback resistors in the Cherry-Hopper amplifiers, a variable gain from -17.4dB to 52.7dB can be obtained. The DC offset is reduced effectively by the use of dual feedback DC-offset cancellation network. The proposed VGA achieves a 3-dB bandwidth of 1GHz with 70.1dB gain turning range. It consumes 9mW through a 1.8V voltage supply. By avoiding the use of broadbanding techniques, such as peaking inductors, the amplifier cell only occupy an area of 38µm×80µm (excluding the bondpads).