Low Voltage, Low Power G_m -C Filter for Low Frequency Applications

This paper describes a low voltage, low power Transconductance-C (G_m -C) filter for low frequency applications. A tunable bulk-driven transconductor is proposed to realize the filter. The transconductance (G _m) is tunable from 8 nS to 90 nS, which is suitable for low frequency G_m -C filters. The transconductor consumes a power of 86 nW. To evaluate the performance of the proposed transconductor, a 2nd order Butterworth low pass filter (LPF) is designed. The cutoff frequency of the filter is tunable from 74 Hz to 820 Hz. The filter offers a dynamic range of 52 dB while consuming a power of 248 nW for a nominal cutoff frequency of 456 Hz. The circuit has been designed and simulated in UMC 180 nm technology with a supply voltage of 0.5 V.