A 1.2-V CMOS front-end for LTE direct conversion SAW-less receiver

A CMOS RF front-end for the Long-Term Evolution (LTE) direct conversion receiver is presented in this paper. With low noise transconductance amplifier (TCA), current commutating passive mixer and transimpedance operational amplifier (TIA), the RF front-end structure enables high-integration, high linearity and simple frequency planning for LTE multi-band applications. Large variable gain is achieved using current-steering transconductance stages. A current commutating passive mixer with 25% duty-cycle LO improves gain, noise and linearity. Direct coupled current-input filter (DCF) is employed to suppress the out-of-band interferer. Fabricated in a 0.13-μm CMOS process, the RF front-end achieves 45dB conversion voltage gain, 2.7dB N F, -7dBm IIP3, and +60dBm IIP2 with calibration from 2.3GHz to 2.7GHz. The total RF front end with divider draws 40mA from a single 1.2-V supply.