A Low-Power Low-Noise Biomedical Instrumentation Amplifier Using Novel Ripple-Reduction Technique

Abstract

This paper presents a low-power low-noise capacitively-coupled chopper instrumentation amplifier (CCIA), which is suitable for biomedical applications such as EEG, ECG and neural recoding. A novel ripple-reduction technique combined with ping-pong auto-zeroing is employed to suppress the ripple at the output of the instrumentation amplifier (IA) by the up-modulated amplifier offset and flicker noise. By using a positive feedback loop in the IA, the IA's input impedance is increased. The complete CCIA is simulated in a standard 0.18 μm CMOS process. The simulated result shows the IA consumes several µA current at 1.8 V supply. The equivalent input noise power spectrum density (PSD) is 54 nV/√Hz and the noise efficiency factor (NEF) achieves 4.05 within 1 kHz, while the equivalent input noise PSD is 55.4 nV/√Hz and NEF is 4.15 within 10 kHz. And the input impedance is about 100MΩ.