Abstract
N-path switched- RC circuits can realize filters with very high linearity and compression point while they are tunable by a clock frequency. In this paper, both differential and single-ended N-path notch filters are modeled and analyzed. Closed-form equa- tions provide design equations for the main filtering characteris- tics and nonidealities such as: harmonic mixing, switch resistance, mismatch and phase imbalance, clock rise and fall times, noise, and insertion loss. Both an eigh t-path single-ended and differen- tial notch filter are implemented in 65-nm CMOS technology. The notch center frequency, which is determined by the switching fre- quency, is tunable from 0.1 to 1.2 GHz. In a 50- environment, the N-path filters provide power matching in the passband with an in- sertion loss of 1.4–2.8 dB. The rejection at the notch frequency is 21–24 dB, ,a n d .