A chopped front-end system with common-mode feedback for real time ECG applications

A Front-End system composed of an instrumentation amplifier with common-mode feedback and a second-order sigma-delta analog to digital converter is proposed. Chopping techniques are used to remove offset and low-frequency noise to guarantee a noise floor below the signal of interest. Measurements show that common-mode feedback adds 71 dB to the CMRR at 50 Hz and the input referred noise is 1.17 μVRMs over the frequency range of 0.1 Hz to 400 Hz.