A CMOS Chopper Amplifier

This paper presents a CMOS chopper amplifier realized with a 2nd order low-pass selective amplifier, using continuous-time filtering technique. The circuit has been integrated in a 3 ¿m p-well low-voltage CMOS technology. The chopper DC gain is 32 dB with 200 Hz bandwidth. The equivalent low-frequency input noise is 63 nV/¿Hz and free from 1/f noise. The input offset is typically 5 ¿V. The amplifier consumes only 34 ¿W and is therefore well suited for biomedical applications, like electrogram amplification.

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