Out-of-Band Immunity to Interference of Single-Ended Baseband Amplifiers Through $IM_{2}$ Cancellation

The effect of second-order intermodulation $(IM_{2})$ 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 $IM_{2}$ distortion generated by local feedback. Measurements of a single-ended amplifier example implementing the proposed method demonstrate an $IP_{2}$ increase of more than 30 dB.