Electronically tunable current-mode OTA-C biquad using two-integrator loop structure

摘要

This paper introduces a current-mode biquad using five operational transconductance amplifiers (OTAs) and two grounded capacitors. The basic circuit configuration is obtained from a second-order integrator loop structure with loss-less and lossy integrators. The biquad circuit can realize low-pass, band-pass, high-pass, band-stop and all-pass transfer functions by suitably choosing the current output branches. And the circuit parameters can also be tuned orthogonally through adjusting the bias currents of OTAs. It is made clear from sensitivity analysis that the biquad enjoys very low sensitivity with respect to the circuit active and passive elements. An example is given together with simulated results by PSPICE.