A High-Input-Impedance Low-Noise Amplifier with Four-Input OTA for Non-Contact ECG Monitoring
Year: 2026
Type: conference-paper
Abstract: This paper presents a low-noise amplifier (LNA) for non-contact electrocardiogram (ECG) acquisition. To mitigate signal attenuation caused by tiny electrode-skin capacitance, the proposed LNA utilizes a four-input folded-cascode OTA that removes the gain-setting input capacitor from the sensing interface, achieving an ultra-high input impedance exceeding $300 \mathrm{G} \Omega$. Furthermore, a temperature-compensation circuit is integrated with a MOS pseudo-resistor bias network to stabilize the high-pass corner frequency against thermal drift up to 100°C. Designed in a 180-nm CMOS process, the LNA consumes $9.3 \mu \mathrm{~A}$ from a 1.2-V supply. Simulation results demonstrate a total input-referred noise of $\mathbf{1 . 5 3} \boldsymbol{\mu} \boldsymbol{V}_{\boldsymbol{r} \boldsymbol{m} \boldsymbol{s}}$ over the $\mathbf{0 . 5}-\mathbf{1 5 0} \mathbf{~ H z}$ ECG bandwidth, ensuring low-noise ECG signal acquisition. The combination of structural decoupling and active temperature compensation ensures robust, high-fidelity signal acquisition, making the proposed LNA highly suitable for low-power noncontact healthcare monitoring applications.
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7204106869