A Broadband Low-Power Low-Noise Active Balun With Second-Order Distortion Cancellation

This paper presents a broadband single-ended input differential output low noise amplifier exploiting IM2 cancelling. A linear feedback from the common mode output to the single-ended input effectively cancels the second-order distortion products in the differential output. The feedback path can be designed for minimum noise, leading to equal or lower noise compared to the amplifier without feedback. A replica bias ensures reduced sensitivity to process, supply voltage and temperature variations. The measured IIP2 across the band from 230 MHz to 470 MHz, varies from 19 to 26 dBm when the feedback is disabled and from 28 to 34 dBm when the feedback is enabled. Measured NF is 2.25 dB in the VHF band and between 2 and 4 dB in the UHF band. Power dissipation is 7.8 mW .