A 180-µW, 120-MHz, Fourth Order Low-Pass Bessel Filter Based on FVF Biquad Structure

This paper proposes a new biquad structure based on a flipped voltage follower (FVF) for low-power and wide-bandwidth (BW) low pass filter. The proposed biquad structure consists of an FVF and a source follower (SF) for complex pole pair generation and zero cancellation. The presented design provides good linearity at low power consumption, owing to the voltage follower structures. A power/BW ratio (PBWR) is suggested as a performance metric to compare power efficiency to bandwidth, and the proposed biquad structure shows excellent PBWR, especially for low quality factor (Q) design. As a prototype, a fourth order Bessel filter was fabricated in 0.18µm CMOS technology. The measured BW, power consumption, IIP3, and FoM are 120MHz, 180µW, 15dBm, and 0.34fJ, respectively.