A 150-μW 3rd-order butterworth passive-switched-capacitor filter with 92 dB SFDR

For the first time, complex conjugate poles are integrated on silicon by using only switches and capacitors. A general design methodology is proposed to implement low-pass transfer functions with sharper frequency profile compared to the passive-switched-capacitor topologies present in the literature. Theory and simulation results are validated through the measurements of a 0.13μm prototype filter. The 3rd-order filter has a cut-off frequency of 540 kHz, an integrated input referred noise of 17μV and out-of-band IIP3 of 55dBm, while consuming 150μW in the phase clock generator.