Low Noise and Low Distortion Telescopic OTA for Biomedical Signal Processing

Abstract

Background: This paper presents a low noise and low distortion telescopic Operational Trans-conductance Amplifier (OTA) that is suited to biomedical signal processing. In our proposal, source degeneration using CMOS transmission gate is introduced in telescopic OTA to realize current- voltage negative feedback. The negative feedback degenerates Gm, reduces flicker noise and reduces distortion. Methods: The circuit is simulated by using TSMC 90nm CMOS process technology with 1.8V supply voltage. We obtained promising simulation results that show THD less than -90dB and flicker noise 60 nV at 4kHz corner frequency. Results: The frequency response plot reveals that our circuit offers a voltage gain of 63dB with negative feedback and achieves a phase margin of about 70 degrees. Thus, this topology is a feasible solution for low noise and low distortion biomedical signal amplifier circuits. Conclusion: A highly linear and low noise telescopic OTA topology was proposed in this paper. A simple but efficient technique of source degeneration is used with negative feedback to achieve low distortion and low noise.