Out-of-Band Immunity to Interference of Single-Ended Baseband Amplifiers Through IM2 Cancellation

摘要

The effect of second-order intermodulation (IM2) distortion produced by out-of-band, high-frequency interference on baseband/IF amplifiers is analyzed using the Volterra series. It is shown that a compensation loop designed to trap nonlinear currents improves the immunity of differential stages to IM2 distortion generated by local feedback. Measurements of a single-ended amplifier example implementing the proposed method demonstrate an IP2 increase of more than 30 dB.