Feedback biasing in nanoscale CMOS technologies

  • Authors:
  • Tajeshwar Singh;Trond Sæther;Trond Ytterdal

  • Affiliations:
  • Department of Electronics and Telecommunications, Norwegian University of Science and Technology, Trondheim, Norway;Department of Electronics and Telecommunications, Norwegian University of Science and Technology, Trondheim, Norway;Department of Electronics and Telecommunications, Norwegian University of Science and Technology, Trondheim, Norway

  • Venue:
  • IEEE Transactions on Circuits and Systems II: Express Briefs
  • Year:
  • 2009

Quantified Score

Hi-index 0.01

Visualization

Abstract

This work rediscovers the attractiveness of feedback biasing when applied to circuits designed in nanoscale CMOS technologies. It is shown that very compact amplifiers can be obtained by utilizing a type of biasing that imposes minimal area overhead. We discuss how the undesired features of the nanoscale CMOS technologies actually help in the revival of this simple biasing method in newer technology generations. The measurement results of prototyped common-source (CS) amplifiers utilizing feedback biasing for application in medical ultrasound imaging systems are presented in this brief. The proposed feedback biasing is also suitable for amplifying signals from high-impedance sources that pose challenges on maintaining high input impedance for the voltage amplifiers while maintaining a very low input capacitance value. Measurements show that the proposed amplifier achieves a Voltage gain of 28 dB, an output noise power spectral density of 0.11 (µV)2/Hz at center-frequency, and a total harmonic distortion of -30 dB, with the full-scale output at 30 MHz, while drawing 120 µA from a 1-V power supply. The amplifiers were fabricated in 9O-nm CMOS technology and measured to be just 20 µm × 10 µm.