A Fifth-Order 20-MHz Transistorized-$LC$ -Ladder LPF With 58.2-dB SFDR, 68-$\mu\hbox{W/Pole/MHz}$ Efficiency, and 0.13-$\hbox{mm}^{2}$ Die Size in 90-nm CMOS

A novel transistorized-
$LC$
-ladder low-pass filter (LPF) is realized by combining source followers with
$Q$
-enhanced floating differential active inductors. It features a small number of active devices to minimize the sources of nonlinearity and noise and a robust frequency response against process variations and device mismatches. A fifth-order 20-MHz LPF prototype is fabricated in 90-nm CMOS. It measures a 58.2-dB spurious-free dynamic range with 6.8 mW of power, which corresponds to a selectivity efficiency of 68-
$\mu \hbox{W}/\hbox{pole}/\hbox{MHz}$
favorably comparable with the state of the art. The die size is merely 0.13
$\hbox{mm}^{2}$
.