Low-Voltage Low-Noise High-CMRR Biopotential Integrated Preamplifier

This work presents a novel amplifier architecture which is the input stage of an analog front end targeting the acquisition of biological signals with low voltage supply (1.2 V), low noise, high Common Mode Rejection Ratio (CMRR) and high current efficiency. A prototype, designed and fabricated in a 130 nm CMOS technology, was characterized by simulations and measurements. Our preamplifier presents one of the lowest noise levels reported up-to-date (over the considered bandwidth) while presenting a very competitive performance in other important features. Results from measurements show a bandwidth from 20 Hz to 11 kHz, a CMRR higher than 70 dB, an equivalent input-referred noise as low as 1.3 μV
_rms
. The Noise Efficiency Factor (NEF) at 2.5 and Power Efficiency Factor (PEF) at 7.5 are remarkable results.