A low distortion wideband active-RC filter for a multicarrier base station transmitter

A fifth order elliptic active-RC low-pass filter with an on-chip capacitor tuning for a highly integrated multicarrier base station transmitter is presented. The cutoff frequency of 16.5 MHz and high linearity are achieved with the folded cascode operational amplifiers, which achieve a large GBW, high linearity and insensitivity to the process and temperature variations. The THD level of over -75 dBc is achieved with a 1 V p-p, 5.4 MHz test signal. A modern 0.35 /spl mu/m, 3.3 V CMOS process is used.