A Passive-Mixer-First Acoustic-Filtering Chipset Using Mixed-Domain Recombination

A mixer-first acoustic-filtering high-intermediate-frequency (IF) superheterodyne radio frequency (RF) front end is presented, which utilizes a mixed-domain recombination architecture. By having a set of commutated switches or essentially a passive mixer before fixed-frequency acoustic filters, mixer-first acoustic filtering enables a widely tunable RF for the front end while preserving the acoustic filter's high-order filtering response and high linearity. Compared to the prior work that uses IF-only recombination, the proposed IF-and-baseband mixed-domain recombination supports a wider instantaneous bandwidth (BW) and higher RF while reducing the number of IF passive components that are lossy and bulky. A proof-of-concept chipset is demonstrated; it consists of an RF front-end N-path commutated-LC passive mixer and an IF in-phase and quadrature (I-Q)-mismatch-compensating complex receiver in 65-nm CMOS as well as two 2.6-GHz Qorvo QPQ1285 bulk-acoustic wave (BAW) filters. In measurement, the chipset operates across 3.5-6.5 GHz RF with a 160-MHz instantaneous BW, 10-dB noise figure (NF) at 3.5-GHz RF, and an out-of-band IIP3 of +27 dBm at 1 x BW offset.