CDBA BASED ANALOG CIRCUIT DESIGN

Abstract

The development in modern analog signal processing applications in the past two decades has lead to evolution from voltage mode realization to current mode analysis. In current mode, the information or signal are processed in the form of current. This shift has acquired its place in electronics circuits as better signal linearity, higher bandwidth, low voltage swing and low supply voltage requirements are the key features of CM circuits. This popularity of current-mode circuits lead to development of various current mode building blocks. Current Differencing Buffered Amplifier (CDBA) is one of them, this block processes the currents applied at its input terminals, thus due to this current processing it inherits all the advantages of the current-mode technique. Also as both current and voltage outputs are available respectively at low and high impedance nodes; this block provides further flexibility in designs. This block can be used for high frequency operation as it is free from parasitic capacitances due to internally grounded input terminals. In this thesis elaborate discussion on the realization of CDBA block and applications such as Filters, Quadrature oscillators and Astable multivibrators based on the CDBA active block is done. Also the realizations discussed are simulated for verification of their operation. Systematic approaches to develop three new oscillator circuits, namely unconditional QOs, third order QOs and Multiphase sinusoidal oscillators are presented. These approaches are used to yield the circuits using CDBA active block. The workability of the proposed circuits is confirmed through Pspice simulations using commercially available AD844 IC’s macro model which is used for the implementation of CDBA block, also third order QO is verified experimentally as well.