A high gain low noise amplifier for implantable cardio technologies

Increase in large number of neurological and cardiovascular illness that cannot be treated by medicine alone have brought about a critical development in the quantity of patients that require implantable electronic gadgets. These gadgets ordinarily contain a sensor to distinguish quiet biomarkers. However, the detected signals are extremely feeble to be further processed and are easily prone to noise. Henceforth, a low noise amplifier (LNA) is utilized post sensor to intensify the frail signal and to decrease the impact of noise. These amplifiers in implants present explicit designing difficulties, including low power utilization and low noise performance. This paper mainly focuses on the low power, high gain, and low noise amplifier suitable for ECG signal acquisition systems to record the electrical motion of a patient’s heart. As LNA is the most power thirsty block of the signal acquisition system, low power LNA suitable for cardio implantable technologies are reviewed and based on the review, a customized LNA design for the respective application is proposed. Proposed LNA is a two-stage operational transconductance amplifier (OTA) whose self-biased driving circuit of the second stage is embedded in the output path of the first stage to reuse current of the first stage. It is designed using 45 nm CMOS technology files, and provides a gain of 42.3 dB, while consuming a power of only 153 nW from 1.2 V single power supply and with an input referred noise of 1.5 μVrms. The proposed amplifier performance satisfies the required parameters of the cardiac implantable devices.