6.7 GHz high-Q active inductor design using parasitic cancellation with process variation control

A correction to a previously published Q- and bandwidth-enhancing design technique using parasitic cancellation to obtain a high-Q active inductor operating at frequencies above 6 GHz using non-minimal-length CMOS technologies is presented. A measured inductance of 1.9 nH is acheived at 6.75 GHz with a Q of 38 occupying only 0.0026 mm2 silicon chip area. The active inductor is then used to obtain a narrowband output matching element for an LNA with its input unmatched in 130 nm CMOS technology. The input-unmatched inductorless LNA parameters measured at 6.7 GHz are: S21 12.8 dB, 3.5 GHz BW, NF 7.2 dB (with simulated NFmin of 3.3 dB) and S22 less than −20 dB, while consuming only 6.4 mW with a 1.2 V supply. The high NF can be easily reduced to NFmin with input matching.