A Low-Power Highly Reconfigurable Analog FIR Filter With 11-Bit Charge-Domain DAC for Narrowband Receivers

An innovative, highly reconfigurable charge-domain analog finite-impulse-response (AFIR) filter for high-channel selectivity receivers is presented. This filter demonstrates excellent reconfigurability to different bandwidths and desired stopband rejection and realizes the coefficients in the charge-domain with time-varying pulse widths controlling the on-time of the transconductor. The charge-domain finite impulse response (FIR) principle is derived step by step in this letter. The proposed filter, manufactured in 28-nm CMOS process, occupies a compact area of 0.05 mm 2, and its bandwidth can be reconfigured from 0.37 to 4.6 MHz. The filter can achieve −70-dB stopband rejection with a sharp transition ( $-f_{-60 {\mathrm {dB}}}^{/f}-3~ {\mathrm {dB}}\,\,=$ 4.5) and low-power consumption of 0.356 mW.