Design and Implementation of Low Noise Amplifier and Variable Gain Amplifier for ECG Systems

This paper explores the needs of key blocks in Analog Front-End integrated circuits, containing a low noise amplifier (LNA) and Variable gain amplifier (VGA) for ECG (electrocardiogram) applications.In this paper, the "Low Noise Amplifier" comprising a two phase fully differential OTA, which gives a gain of 45.9dB. The signal-to-noise ratio of the LNA is 18.62dB and 24.89dB for Von and Vop respectively and voltage gain of 44.14dB. In an Analog to digital converter, variable gain amplifier is a critical component for amplification process. In addition, variable gain amplifier is employed for further amplification, which provides gain of 25dB. The Analog Front End proposed in our paper is specially designed for low power. Analog Front End (AFE) is implemented in Cadence virtuoso by using 180 nm CMOS technology with a power supply of 1.8V.