Micropower transconductor for very-low frequency filters

A very simple approach to realize very-low frequency continuous-time filters is proposed. The very-low cutoff frequencies are achieved by the use of very-small transconductance transconductor which is based on the cascading of g/sub m/-g/sub m//sup -1/. For demonstration, a first-order g/sub m/-C lowpass filter was designed and simulated. The simulation results confirming the theory showed that 5 Hz and 10 Hz cutoff frequencies can be obtained with the power dissipation of 88 nW and 66 nW, respectively, while the integrating capacitor is only 1 pF.