A G _m -C continuous-time analog filter for IEEE 802.11 a/b/g wireless LANs

摘要

A CMOS transconductor for multi-mode wireless channel selection filter is presented. The linear transconductor is designed based on the flipped-voltage follower (FVF) circuit and an active resistor to achieve the transconductance tuning. The transconductance tuning can be obtained by changing the bias current of the active resistor. A third-order Butterworth low-pass filter implemented with the transconductors was designed by TSMC 0.18-μm CMOS process. The results show that the filter can operate with the cutoff frequency of 10–20 MHz. The tuning range would be suitable for the specifications of IEEE 802.11 a/b/g Wireless LANs under the consideration of saving chip areas. In the design, the maximum power consumption is 13 mW with the cutoff frequency of 20 MHz under a 1.8 V supply voltage.