A Wideband Inductorless LNA Employing Active Complementary Current-Reuse Balun

This paper presents a new fully-integrated CMOS single-to-differential low-noise amplifier (LNA) topology for cognitive radios. Operating from 50 MHz to 5 GHz, the proposed wideband LNA uses two current-reuse shunt-feedback (SFB) amplifiers as the core circuit and an inverter amplifier as the active balun. The transconductance of the amplifiers is boosted by utilizing both nMOS and pMOS transistors in complementary structures. Designed in TSMC 0.18 μm CMOS technology, the LNA achieves a voltage gain of 25.3 dB and a noise figure of 3.6 to 5.0 dB, with a power dissipation of 16.7 mW. The complementary characteristics leads to partial second-order distortion cancellation. The achieved IIP3 and IIP2 are from 0 to 9.5 dBm and > 31 dBm, respectively. The proposed inductorless balun-LNA is post-layout simulated and it occupies only 0.0094 mm
²
.