A 2 V low-distortion CMOS biquadratic cell

This paper presents a fully differential CMOS biquadratic cell using an active-C integrator at a 2 V supply voltage. An operational transconductance amplifier is used based on grounded MOS transistors biased in the triode region by a simple current conveyor. DC measurements validate the high linearity of the transconductor. The transconductor achieves inherently a high transconductance to current ratio which can be further increased by degenerating the current conveyor. The integrator does not require any additional input common-mode rejection circuit and has an inherent output common-mode stabilization circuit, making it very compact. The biquadratic cell shows a total harmonic distortion of -60 dB for a 500 kHz 1 Vpp signal. The power dissipation per pole is 300 /spl mu/W.