Widely Tunable 4th Order Switched G -C Band-Pass Filter Based on N-Path Filters Milad Darvishi, Student Member , IEEE , Ronan van

Abstract

A widely tunable 4th order BPF based on the subtrac- tion of two 2nd order 4-path passive-mixer filters with slightly dif- ferent center frequencies is proposed. The center frequency of each 4-path filter is slightly shifted relative to its clock frequency (one upward and the other one downward) by a -C technique. Ca- pacitive splitting of the input signal is used to reduce the mutual loading of the two 4-path BPFs and increase their quality factors. The filter is tunable from 0.4 GHz to 1.2 GHz with approximately constant bandwidth of 21 MHz. The in-band 1-dB compression p o i n to ft h efilter is 4.4 dBm while the in-band IIP of the filter is 9 dBm and the out-of-band IIP is 29 dBm ( 50 MHz). The ultimate rejection of the filter is 55 dB and the NF of the filter is 10 dB. The static and dynamic current consumption of the filter are 2.8 mA from 2.5 V and 12 mA from 1.2 V , respectively (at 1 GHz). The LO leakage power to the input port is 60 dBm. The filter has been fabricated in CMOS LP 65 nm technology and t h ea c t i v ea r e ai s0 . 1 2 7m m.