An active device based wide tuning range CMOS transconductor

A CMOS transconductor for wide tuning range filter application is presented. The linear transconductor is designed based on the flipped-voltage follower (FVF) circuit and can work in the weak, moderate, and strong inversion regions to maximize the transconductance tuning range. The transconductance tuning can be achieved by changing the bias current of the active resistor, and a ratio of 28 is obtained. The transconductor was evaluated by using TSMC 0.18 μm CMOS process, and the total harmonic distortion (THD) of -56 dB can be obtained by giving a 12 MHz 0.4 Vpp input swing signal. In the design, the maximum power consumption is 2 mW with the transconductance of 1.1 mS under a 1.8 V supply voltage.