A CMOS 3rd Order Gm – C Lowpass Filter design for Electroencephalography

This paper presented the OTA design with techniques to generate lower transconductance used in an operational transconductance amplifier-capacitor (g <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf> -c) filter to achieve lower bandwidth requirements as EEG signals range from 0 to 200Hz. The proposed OTA used cross coupled network, source degeneration and current division techniques to generate lower transconductance. The OTA designed for low power consumption utilizes 1 V power supply with 15 nA biasing current. The EEG filter designed by cascading 3 g <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf> -c filters. The filter simulated in Cadence virtuoso UMC 180-nm technology, achieved bandwidth 203 Hz with pass band gain of 1.76 dB, input referred noise 64 μ Vr m s and power consumption of 69 nW.