A self-oscillating LNA-mixer

In this paper, a new circuit topology to realize a stacked self-oscillating LNA-Mixer is proposed. The basic idea has been to recognize that in a high-performance down-conversion mixer its RF input-stage gain, linearity, and noise tradeoff is often improved by feeding it with a bypass current source. This current source could be isolated with an inductor so as to allow free implementation of the oscillator block on top of it. Using these guidelines, the presented circuit achieves high-performance without sacrificing compatibility with modern low-voltage CMOS implementations. To further demonstrate usefulness of the circuit, an entire single-stage quadrature (IQ) RF front-end using this circuit as a core has been developed. The IQ front-end, targeted for the Galileo satellite navigation system, has been designed using a 65-nm CMOS technology, and it achieves NF=4.4 dB, IIP3=-15 dBm and A_v=25 dB at 1.575 GHz, while using only 1 mA from the low 1.2-V supply.