A 4.35-mW +22-dBm IIP3 continuously tunable channel select filter for WLAN/WiMax receivers in 90-nm CMOS

A low-power high linearity CMOS Gm-C channel select filter for WLAN/WiMax receivers in 90-nm CMOS technology is presented. To reduce power consumption a biquad cell with simple architecture and few devices is used. A simple but efficient technique is also used to improve the linearity of the filter without increasing its power consumption. The cutoff frequency of the sixth order Butterworth low-pass filter can be tuned from 8.1 to 13.5 MHz for WLAN and WiMax applications. The measurement results show an in-band IIP3 of +22 dBm and an input referred noise of 75 nV/√Hz at a power consumption of 4.35 mW from a 1-V supply. The differential filter occupies a chip area of 0.239 mm2 excluding pads.