A 65 nm CMOS resistive feedback noise canceling LNA with tunable bandpass from 4.6 to 5.8 GHz

Abstract

Two low-noise amplifiers (LNA) with single ended input and differential output (balun) for multi-standard wireless receivers up to 6 GHz are presented. The proposed LNA's are based on resistive-feedback concept, which enables wide-band input impedance matching and gain. A measured test structure of the first LNA shows a wide-band gain of 22 dB in a band of 0.2---5 GHz. Due to different noise cancellation techniques, the proposed LNA achieves a superior low noise figure (NF) of 1.7 dB at 2.5 GHZ. The IIP3 linearity and 1 dB compression point of the LNA are about ?4 and ?16.1 dBm at 2 GHz respectively. To relax external RF filters and LNA linearity requirements, a second LNA version with an on-chip LC bandpass load enabling a tunable center frequency from 4.6 to 5.8 GHz is presented. The LNA achieves a measured gain up to 30 dB and an IIP3 linearity between ?6.5 and ?10.3 dBm. The NF reaches a low value of 1.6 dB in the band of interest. Both LNA circuits are implemented in 65 nm CMOS technology with an active chip area of 112 × 78 and 154 × 197 μm2 respectively. Therefore the proposed LNA structures are a cost-effective alternative to source-degeneration based narrow-band LNA's with comparable performance. Since wide-band input impedance matching is employed, the LNA's can be used in re-configurable multi-standard wireless low-cost applications.