Optimizing Power Consumption vs. Linearization in CMFB Amplifiers with Source Degeneration

摘要

In this work, a low power consumption approach to achieve linear Differential Difference Amplifier CMFB circuits is introduced. A solution based on source degeneration in the input differential pairs is proposed to reduce input range linearity limitations as well as CMFB input pair large current consumption by accurately selecting both current and degeneration resistance to maximize linearity. The proposed technique has been implemented in a CMFB amplifier of a fully differential OTA, resulting in a THD of 0.026% when using degeneration resistances of 48 mΩ and 53.3 μ A of bias current. Moreover, linearity improvement using the proposed technique has shown better figures than increasing only the bias current.