A 0.8 V, 14.76 nVrms, Multiplexer-Based AFE for Wearable Devices Using 45 nm CMOS Techniques

Esther Tamilarasan; Gracia Nirmala Rani Duraisamy; Muthu Kumaran Elangovan; Arun Samuel Thankmony Sarasam

doi:10.3390/mi14101816

A 0.8 V, 14.76 nVrms, Multiplexer-Based AFE for Wearable Devices Using 45 nm CMOS Techniques

Micromachines (Basel). 2023 Sep 23;14(10):1816. doi: 10.3390/mi14101816.

Authors

Esther Tamilarasan¹, Gracia Nirmala Rani Duraisamy¹, Muthu Kumaran Elangovan², Arun Samuel Thankmony Sarasam³

Affiliations

¹ Department of Electronics and Communication, Thigarajar College of Engineering, Madurai 625005, Tamil Nadu, India.
² Engineering, D.R.B.R. Ambedkar Institute of Technology, Port Blair 744101, Union Territory of Andaman & Nicobar Islands, India.
³ Department of Electronics and Communication , National Engineering College, Kovilpatti 628503, Tamil Nadu, India.

Abstract

Wearable medical devices (WMDs) that continuously monitor health conditions enable people to stay healthy in everyday situations. A wristband is a monitoring format that can measure bioelectric signals. The main part of a wearable device is its analog front end (AFE). Wearables have issues such as low reliability, high power consumption, and large size. A conventional AFE device uses more analog-to-digital converters, amplifiers, and filters for individual electrodes. Our proposed MUX-based AFE design requires fewer components than a conventional AFE device, reducing power consumption and area. It includes a single-ended differential feedback operational transconductance amplifier (OTA) and n-pass MUX-based AFE circuits which are related to the emergence of low power, low area, and low cost AFE-integrated chips that are required for wearable biomedical applications. The proposed 6T n-pass multiplexer measures a gain of -68 dB across a frequency range of 100 kHz with a 136.5 nW power consumption and a delay of 0.07 ns. The design layout area is approximately 9.8 µm² and uses 45 nm complementary metal oxide semiconductor (CMOS) technology. Additionally, the proposed single-ended differential OTA has an obtained input referred noise of 0.014 µV_rms, and a gain of -5.5 dB, while the design layout area is about 2 µm² and was designed with the help of the Cadence Virtuoso layout design tool.

Keywords: CMOS; Cadence Virtuoso; analog front end (AFE); analog multiplexer; operational transconductance amplifier; wearable medical devices (WMD).

Grants and funding

This research received no external funding.