A Frequency-Selective Broadband Low-Noise Amplifier With Double-Loop Transformer Feedback

A frequency-selective, power-to-current ( P- I) broadband low-noise amplifier (FS-LNA) is presented. The use of global and/or local feedback in tandem is investigated, where monolithic transformers realize the feedback loops. Superior performance is realized when global and local feedbacks are interwound. A cascode gain stage with a current-to-current positive feedback loop to boost the power gain and a current-to-current negative feedback loop for impedance and/or noise matching is implemented in 90 nm RF-CMOS. The FS-LNA also provides at least 20 dB RF signal rejection at frequencies below the L-band (includes GPS and GSM carriers). The measured gain, noise figure and 1-dB gain compression point of the LNA from 3.5-9.25 GHz are 15±3 dB, 2.4 ±0.8 dB and -17.5 ±2.5 dBm, respectively. The chip area of the LNA is 0.7 × 0.8 mm². The FS-LNA consumes 9.6 mW from a 0.8 V power supply. It is most suitable for sub-1 V single-cell integrated radios and can be used for multiband/multistandard wireless technologies, such as broadband impulse-radio ultra-wideband (IR-UWB) and frequency modulated (FM) UWB.