A 2.1 to 6 GHz Tunable-band LNA With Adaptive Frequency Responses by Transistor Size Scaling

A 2.1 to 6 GHz tunable-band LNA by using transistor-size scaling technique is realized in 90 nm CMOS technology, which adopts a scalable-size transistor mimicked by the parallel-connected transistors with binary weighted device sizes. In the 16 programmable bands located in the frequencies of interest, the S21 varies in the range from 15.1 to 16.9 dB, and the NF is from 2.16 to 2.81 dB. This tunable -band LNA occupies only 0.23 mm
²
, which is readily compact compared with the prior arts of passive components switchable LNAs.