A CMOS chopper-stabilized differential difference amplifier for biomedical integrated circuits

A new CMOS chopper-stabilized differential difference amplifier (CHSDDA) that exploits the combination of chopper technique with differential difference amplifier is proposed, with advantages for use in instrumentation circuits requiring floating differential input and single-ended output. When configured as an instrumentation amplifier (IA), it operates as the analog front-end (AFE) for an electroencephalogram (EEG) recording system in integrated biomedical systems. The measurement results have shown that it achieves 1/f noise reduction, CMRR more than 120 dB (0-700 Hz), dc offset less than 16.5 /spl mu/V and current drain of 150 /spl mu/A at a 3 V single supply using a standard 0.6 /spl mu/m CMOS technology.