Re-configurable Gain, Bandwidth, Chopper Stabilized, Biosignal Amplifier Design In 180nm CMOS Process

An amplifier design with re-configurable gain and bandwidth is presented in the paper for the amplification of three biopotential signals: the electrocardiogram (ECG), the electroencephalogram (EEG), and neural signals. This amplifier uses chopper stabilization to decrease the input-referred noise (IRN) and suppresses the low-frequency flicker noise. The proposed circuit operates in two modes and is designed in 180nm CMOS technology. The low pass frequency is set at 0.03 Hz to 1 Hz, and the upper pass frequency is set at 150 Hz - 5 kHz. With a closed-loop gain of 35.5 dB - 60 dB, the amplifier exhibits $3.61 \mu \mathrm{W}$ of power consumption for 1.8 V supply and $0.3 \mu \mathrm{V}_{rms}$ of input-referred noise over the range 0.1 Hz to 150 Hz. With action potential neural signals (0.1 Hz - 5 kHz), the amplifier i s configured with input-referred noise of $2.63 \mu \mathrm{V}_{rms}$. Inclusion of the chopper stabilization circuit decreased the IRN by 86.6%, and 77.6%, to $0.04{\mu} \mathrm{V}_{rms}$and $0.58{\mu} \mathrm{V}_{rms}$, respectively.