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

Area of Science:

• Biomedical Engineering
• Integrated Circuit Design
• Wearable Technology

Background:

• Wearable medical devices (WMDs) are crucial for continuous health monitoring, but often suffer from high power consumption and large sizes.
• Conventional analog front end (AFE) designs for WMDs utilize numerous components, leading to inefficiencies.
• Wristband-based devices for measuring bioelectric signals face challenges in reliability, power, and size.

Purpose of the Study:

• To propose a novel multiplexer (MUX)-based AFE design for WMDs.
• To reduce component count, power consumption, and area in wearable AFE chips.
• To develop low-cost, low-power, and small-footprint AFE-integrated chips for biomedical applications.

Main Methods:

• Implemented a single-ended differential feedback operational transconductance amplifier (OTA).
• Designed an n-pass MUX-based AFE circuit.
• Utilized 45 nm complementary metal oxide semiconductor (CMOS) technology and Cadence Virtuoso for design and layout.

Main Results:

• The proposed 6T n-pass multiplexer achieved a gain of -68 dB at 100 kHz, with 136.5 nW power consumption and 0.07 ns delay.
• The MUX-based AFE design layout area is approximately 9.8 µm².
• The single-ended differential OTA exhibited an input-referred noise of 0.014 µVrms and a gain of -5.5 dB, with a layout area of ~2 µm².

Conclusions:

• The MUX-based AFE design offers a significant reduction in component count, power consumption, and area compared to conventional designs.
• This approach enables the development of more efficient and compact AFE-integrated chips for wearable biomedical applications.
• The proposed design contributes to the advancement of reliable and cost-effective WMDs for everyday health monitoring.