An improved common-mode feedback loop for the differential-difference amplifier

  • Francesco Centurelli
  • Andrea Simonetti
  • Alessandro Trifiletti
Article

Abstract

Unconditional stability of the high-gain amplifiers is a mandatory requirement for a reliable steady-state condition of time-discrete systems, especially for all blocks designed to sample-and-hold (S/H) circuits. Compared to differential path, the common-mode feedback loop is often affected by poles and zeros shifting that degrades the large signal response of the amplifiers. This drawback is made worse in some well-known topologies as the difference-differential amplifier (DDA) that shows non-constant transconductance and poor linearity. This work proposes a body-driven positive-feedback frequency compensation technique (BD-PFFC) to improve the linearity for precision DDA-based S/H applications. Theoretical calculations and circuit simulations carried out in a 0.13 μm process are also given to demonstrate its validity.

Keywords

Positive-feedback compensation Differential difference amplifier Common-mode feedback loop Sample-and-hold circuits 

Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  • Francesco Centurelli
    • 1
  • Andrea Simonetti
    • 1
  • Alessandro Trifiletti
    • 1
  1. 1.Department of Information Engineering, Electronics and Telecommunications (DIET)University of Rome “La Sapienza”RomeItaly

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