Low-power widely tunable Gm-C filter with an adaptive DC-blocking, triode-biased MOSFET transconductor

We propose a new transconductor to achieve a wide continuous-tuning-range filter applicable to IEEE802.11a/b/g W-LANs, W-CDMA, and Bluetooth, without sacrificing power consumption. The wide tuning range is achieved by employing triode-biased input MOSFETs, whose transconductance is widely tuned with drain bias. The transconductor also employs an adaptive DC-blocking circuit that suppresses any idle current in the high transconductance mode, resulting in minimizing the power consumption of the transconductor. A 4th-order Butterworth low-pass filter, using this new transconductor, exhibits a cutoff frequency tuning range of 0.5-12 MHz with power consumption of 1.1-4.7 mW. The tuning range is 5 times wider than other works with low power consumption.