IMPLEMENTATION OF ANALOG CIRCUITS USING CD-DITA

Abstract

CD-DITA based basic filtering applications such as first order APF and current mode SIMOtype universal biquad filter have been implemented and CD-DITA based grounded inductor and mixed mode filter have been proposed. CD-DITA is an extension of CDTA having extra voltage input than CDTA increasing its usability of differential inputs. For a suitable CMOS based implementation of CD-DITA, several CDTA realizations are studied and the suitable one is modified to implement the proposed CD-DITA block. A FVF based CD-DITA is characterized and its applications in analog signal processing circuits such as basic current amplifier, adder subtractor and integrator are also studied. The proposed CD-DITA based grounded inductor is realized with one resistors and one capacitor and further using proposed inductor band pass filter has been simulated. The proposed CD-DITA based mixed mode filter using two resistors and two capacitors with independent tuning of natural frequency and quality factor is simulated. The proposed filter also offers low active and passive sensitivities. In addition, the effects of parasitics and errors on the proposed filter are also investigated. The characteristics of CD-DITA and its applications are verified by PSPICE simulations using TSMC 0.25μm CMOS technology. The characteristics of CD-DITA and validity of proposed biquad filter is verified by SPICE simulation using TSMC 180nm technology.