A CMOS analog front-end IC for portable EEG/ECG monitoring applications

A new digital programmable CMOS analog front-end (AFE) IC for measuring electroencephalograph or electrocar-diogram signals in a portable instrumentation design approach is presented. This includes a new high-performance rail-to-rail instrumentation amplifier (IA) dedicated to the low-power AFE IC. The measurement results have shown that the proposed biomedical AFE IC, with a die size of 4.81 [mm.sup.2], achieves a maximum stable ac gain of 10 000 V/V, input-referred noise of 0.86 [micro] [V.sub.rms] (0.3 Hz-150 Hz), common-mode rejection ratio of at least 115 dB (0-1 kHz), input-referred dc offset of less than 60 [micro]V, input common mode range from -1.5 V to 1.3 V, and current drain of 485 [micro]A (excluding the power dissipation of external clock oscillator) at a [+ or -] 1.5-V supply using a standard 0.5-[micro]m CMOS process technology. Index Terms--Analog IC, biomedical circuits and systems, electrocardiogram (ECG), electroencephalograph (EEG), instrumentation amplifier (IA), rail-to-rail amplifier.