A 790 nW Low-Noise Instrumentation Amplifier for Bio-Sensing Based On Gm-RSC Structure

Abstract

This paper presents a low-power low-noise instrumentation amplifier (IA) for bio-potential recording. The proposed IA is based on a novel Gm-RSC structure, whose gain is determined by the transconductance (Gm) and the equivalent resistance ([Formula: see text]) of the switched-capacitor (SC) load. The transconductance amplifier stage is based on the current-reuse telescope topology to achieve low noise at low-power dissipation. A resistor-controlled oscillator is designed to generate desirable operational frequency for SC load and to continuously tune the mid-band gain of the IA for different biomedical applications. Measurement results show that the input referred noise of the proposed IA is about 1.27[Formula: see text][Formula: see text]VRMS ([Formula: see text][Formula: see text]Hz) and the noise efficiency factor is 3.3. The range of tunable gain is from 28 to 40[Formula: see text]dB. The common mode rejection ratio and power supply rejection ratio at 50[Formula: see text]Hz are 72 and 78[Formula: see text]dB, respectively. The IA consumes only 660[Formula: see text]nA current at 1.2[Formula: see text]V supply and the active area of the IA is only 0.035[Formula: see text]mm2.