A 100dB-TCMRR 8-Channel Bio-Potential Front-End with Multi-Channel Common-Mode Replication.

For a multichannel bio-potential signal acquisition front-end, it's total CMRR (TCMRR) is restricted by these three factors: the inherent CMRR (ICMRR) of the amplifier used in the acquisition front-end, the impedance mismatch of electrodes, and the systematic mismatch due to the shared reference electrode. This paper presents a 8-channel bio-potential front-end with multi-channel common-mode replication(MC-CMR). The frontend has been implemented in a standard CMOS 0.18-mu m process, and the measurement results show that the amplifier has an adjustable gain of 46 to 64 dB, the input reference noise within 1Hz to 1k Hz is 1.62 mu V-rms, TCMRR of the front-end is 100dB (at 50Hz). A single channel consumes 1.86 mu A at 1.8V supply voltage, and the NEF is 2.7.