A Pseudo pMOS Resistive OTA with Ultra-Low Noise and PVT-Robust Performance for Smart Neuro-Rehabilitation Wearables

Abstract

In smart wearable devices, a high-performance operational transconductance amplifier (OTA) for portable EEG data collection is designed and analysed for various parameters. With 14.5 nV/Hz input-referred noise, the 130 nm CMOS common source pseudo pMOS resistive OTA architecture can safely amplify weak EEG signals from 0.5 to 100 Hz at 1.8 V With 125 dB CMRR and 77 dB open-loop gain, the amplifier reduces external interference and motion artifacts. 2.2 µW power consumption enhances battery life for continuous monitoring in wearable biomedical devices. Investigation shows 4.59 nV_RMS integrated output noise and 2.11 × 10⁻¹⁷ V² overall noise power. OTA's 1–2 continuous NEF and 1.8–7.2 PEF balance noise and power. Consistent 10 V/µs slew rate ensures accurate signal tracking. Supply variations, process corners, and -40°C to +125°C performance are consistent in extensive PVT simulations. The custom OTA design reduces flicker noise and mismatch using symmetry, local shielding, and common-centroid structures. The layout measures 73.99 µm width and 25.1 µm length, covering 1850 µm² of area. The tiny size suits modern wearable EEG front-ends. These results imply the OTA is a compact, noise-resistant, and energy-efficient analog front-end for smart wearables and BCIs.