A 1.5 V 75 dB-dynamic range 3rd-order Gm-C filter integrated in a 0.18 µm standard digital CMOS process

A design methodology of a CMOS low-voltage linear transconductor for low-power baseband filter applications is proposed in this paper. The transconductor linearization scheme is based on regulating the drain voltage of triode-biased input transistors through an active cascode loop. A 3^rd-order lowpass Butterworth baseband filter implemented with this transconductor is integrated in a 0.18µm standard digital CMOS process. It can operate from 1.2-1.8 V supply voltage with a cutoff frequency ranging from 15 to 85 kHz The dynamic range measured at 1.5 V is 75 dB, while dissipating 240µW.