Multiple output differential OTA with linearizing bulk-driven active-error feedback loop for continuous-time filter applications

摘要

A CMOS circuit realization of a highly linear multiple-output differential operational transconductance amplifier (OTA) has been proposed. The presented approach exploits a differential pair as an input stage with both the gate and the bulk terminals as signal ports. For the proposed OTA, improved linearity is obtained by means of the active-error feedback loop operating at the bulk terminals of the input stage. SPICE simulations of the OTA show that, for 0.35 mu m AMS process, total harmonic distortion at 1.36Vpp is less than 1% with dynamic range equal to 60.1dB at power consumption of 276W from 3.3V supply. As an example, both single output and dual differential OTAs are used to design third-order elliptic low-pass filters. The cut-off frequency of the filters is 1MHz. The power consumption of the OTA-C filter utilizing the dual output differential OTA is reduced to 1.24mW in comparison to 2.2mW consumed by the single output differential OTA-C filter counterpart. Copyright (c) 2014 John Wiley & Sons, Ltd.