Low-Noise Wide-Frequency Tunable Amplifier for Bioimpedance Spectroscopy Applications

Abstract

This paper presents a low-noise energy efficient amplifier for bioimpedance spectroscopy applications. It is based on a capacitor closed loop approach that provides a 40 dB gain set by the ratio of input and feedback capacitors, also avoiding DC offsets. Frequency range can be programmed by tuning both lower and upper cut-off frequencies, therefore achieving bandwidths from few hundreds of kHz to more than 1 MHz. Due to frequency tunability, power consumption varies from 6.2 to $39.6\ \boldsymbol{\mu}\mathbf{W}$. Noise levels remain below $0.2\ \boldsymbol{\mu}\mathbf{V}/\mathbf{Hz}^{1/2}$ for frequencies higher than 100 Hz.