A Passively Gain-Boosted N-Path Band Pass Filter using a Commutated Charge Pump

This paper presents a passively gain-boosted two-port N-path bandpass filter. In the proposed filter, gain-boosting is achieved by commutating a charge-pump. The harmonic transfer function of the proposed filter has been derived and verified through simulations. A prototype four-path passively gain-boosted BPF is designed in a CMOS 65 nm technology and the simulation results are presented. The center frequency of the filter is tunable from 0.2 GHz to 1.2 GHz. Over the tuning range, the filter has a peak gain in-between 7.6 dB and 9.8 dB, NF < 4.7 dB, and IIP3 > 6 dBm.