A 0.2-6 GHz 65 nm CMOS Active-Feedback LNA with Threefold Balun-Error Correction and Implicit Post-Distortion Technique

we propose a wideband low-noise amplifier (LNA) with balun-error correction and linearity enhancement. Towards active feedback LNA in double CS stages, a threefold correction of voltage ratio preset, differential current balancer (DCB), and high-frequency RC compensation is applied to lower balun error across the passband. A linearization structure without penalty of add-on parasitic and noise is proposed herein. The active feedback path is reused as post-linearization to tap and cancel distortion of input CS stages at the LNA outputs. The distortion of the active load is regulated by tuning the output CM level via a CMFB block, to compensate for the residual distortion offset. A CM-DM noise conversion through asymmetry of output resistance is suppressed by the OTA filtering. Measurement results show that within the bandwidth of 0.2-6 GHz, the LNA prototype implemented in standard 65 nm CMOS technology, achieves a gain of 19.5 dB, a noise figure (NF) of 2.8 dB. Across the passband, gain and phase errors are within 0.5 dB and 1° while the average IIP3 reaches 2.5 dBm. The proposed circuit consumes 14.7 mW and occupies core area of $0.095 \mathrm{~mm}^{2}$.