A low-power 84-dB dynamic-range tunable Gm-C filter for bio-signal acquisition

A tunable Gm-C filter is presented for bio-signal acquisition application. It incorporates linear tunable transconductors utilizing MOSFETs biased in the triode region. Both the filter architecture and transconductor circuit design are optimized for good tuning, linearity and noise performance with low power consumption. The filter was fabricated in a 0.6 μm BiCMOS process, occupying 0.17 mm
²
. Measurement results show a tuning range of cut-off frequency from 2.5 kHz to 10 kHz. At 5 kHz cut-off frequency, the filter achieves a dynamic range of 85 dB with 1% THD, and consumes 75.9 μW from 3.3 V supply.