Implementation of a CMOS LNA plus mixer for GPS applications with no external components

A fully differential 0.35-/spl mu/m CMOS LNA plus mixer, for GPS applications, using no external component apart from an input balun, has been realized. The LNA makes use of an inductively degenerated input stage and a resonant LC load, featuring 12% frequency tuning, accomplished by a MOS varactor. The mixer is a Gilbert cell type in which an NMOS and a PMOS differential pair, shunt together, realize the input stage. This topology allows one to save power for given mixer gain and linearity. The front-end measured performances are: 40-dB gain, 3.8-dB NF, -25.5-dBm IIP3, 1.3-GHz input frequency, 140-MHz output frequency, with 8 mA from a 2.8-V supply.