Current-Mode LP CMOS Active Filter for Very Low Frequency Applications

A new structure of a current-mode LP active filter in CMOS technology, suitable for applications in very low frequency filters is presented in the paper. On the basis of this structure, particular solution of a sixth-order Bessel filter has been designed and tested by SPICE simulations. The main features of this design are; very low cutoff frequency (2.4 Hz), very low dissipation power (9 nW) and low supply voltage (1 V with additional auxiliary supply voltage equal to -1 V).