A tuned, inductorless, recursive filter LNA in CMOS

An active recursive filter approach is proposed for the implementation of an inductorless, tuned LNA in CMOS. Such an LNA was designed and fabricated in a 0.8 µm CMOS process. In simulation, the feasibility of this type of LNA was demonstrated, and reasonably good performance was obtained. The fabricated device shows a center frequency tuning range from 250 MHz to 975 MHz. Gain and Q-value are tunable in a wide range. The LNA exhibits an input referred 1 dB compression point of -31 dBm and a noise figure of approximately 3 dB measured at 900 MHz center frequency.