A CMOS image-rejection mixer with 58-dB IRR for DTV receivers

The design, implementation, and characterization of an image-rejection double quadrature conversion mixer based on RC asymmetric polyphase filters (PPF) are presented. The mixer consists of three sets of PPFs and a mixer core for quadrature down conversion. Two sets of PPFs are used for the quadrature generation and the other one is used for the IF signal selection to reject the unwanted image band. Realized in 0.18-μm CMOS technology as a part of the DVB-T receiver chip, the mixer exhibits a high image rejection ratio (IRR) of 58 dB, a power consumption of 11 mW, and a 1-dB gain compression point of −15 dBm.