A CMOS Wideband Linear Low-Noise Amplifier Using Dual Capacitor-Cross-Coupled Configurations

Benqing Guo, Jun Chen

Abstract: A wideband differential common-gate (CG) low-noise amplifier is proposed with dual-capacitor-cross-coupling(CCC) feedforward structures. Besides the noise reduction benefit, the input CCC CG stage boosts the interstage gain to alleviate the trade-off between load headroom and gain. The other CCC structure is applied to an intermodulation distortion source and reduces auxiliary transistors’ scaling by ~8x. The resulting significantly low parasitics are expected to reduce the sensitivity of the post-distortion technique to frequency variations. The configuration of all-nMOS and all-saturation-region bias is to ensure the robustness of linearization. The proposed circuit is fabricated in a 180 nm CMOS process. Experimental results have shown an average value of 14.5 dB gain and 3.1 dB NF across a passband range of 0.2-3.5 GHz. Moreover, the passband IIP3 is shown as 14-19.7 dBm while IIP2 linearity takes ~41.5 dBm. The circuit core consumes 7 mW with a 1.8 V supply and occupies an area of 598×265 μm 2 .