A Wide Linear Range Ultra-low Transconductance Amplifier for Biomedical Sensor Applications

Abstract

In the field of biomedical sensors, active filters with very low cutoff frequencies are required because of the weak electrical signals from the human body. The Gm-C filters are more prominent among the filter designs, which consist of an operational transconductance amplifier (OTA) and a capacitor. The key design issues are transconductance and linearity. In this paper, a new ultra-low transconductance OTA structure is proposed. The basic idea is to extend the linear input range of the OTA using the source degeneration pseudo-resistor technique and the bulk-driven technique. The transconductance is reduced by using series-parallel current mirrors for the OTA. This ultra-low transconductance OTA has an extremely low bias current of 0.1nA and a shunt factor of 100, reducing the OTA transconductance to 0.4 ps with 39.55 μVrms noise. It also increases the linear input range from ±50 mV to ±2.5 V, extending it by a factor of 50.

Haoning Sun

Master’s Student

My research interests include circuit design of analog to digital converter for biomedical applications and noise shaping SAR ADC.

Zhipeng Li

PhD Student

My research interests include circuit design of image sensors and energy harvesting circuits.

Ruihuang Wu

M.Sc.

My research interests include circuit design of delay loop lock.

Feng Yan

PhD Student

My research interests include circuit design of analog front end for biomedical applications and sensor interfaces.

Yuxuan Huang

M.Sc.

My research interests include circuit design of low-power reference.

Jingjing Liu

Associate Professor

My research interests include low-power smart micro-sensor integrated circuit design, image sensors, biomedical sensors, and energy harvesting circuits.