Design of a High Performance 2-GHz Direct-Conversion Front-End With a Single-Ended RF Input in 0.13 $\mu$ m CMOS

A 2.1 GHz CMOS front-end with a single-ended low-noise amplifier (LNA) and a double balanced, current-driven passive mixer is presented. The LNA drives an on-chip transformer load that performs single-ended to differential conversion. A detailed comparison in gain, noise, and second and third order linearity performance is presented to motivate the choice of a current-driven passive mixer over an active mixer. The front-end prototype was implemented on a 0.13 mum CMOS process and occupies an active chip area of 1.1 mm ². It achieves 30 dB conversion gain, a low noise figure of 3.1 dB (integrated from 40 KHz to 1.92 MHz), an in-band IIP3 of -12 dBm, and IIP2 better than 39 dBm, while consuming only 12 mW from a 1.5 V power supply.