DESIGN OF OSCILLATORS USING OTRA

Abstract

The reduction of the minimum feature size of an MOS transistor for digital VLSI circuits has been ongoing for the past few decades. As the channel length is scaled down into deep sub micrometer dimensions, the lower power supply voltage is required to ensure the device reliability. To be compatible with digital VLSI technologies, analogue integrated circuits, which can operate at low supply voltages, are also receiving significant attention. This has resulted in development of various current mode analog building blocks and operational transresistance amplifiers (OTRA).OTRA is high gain current input voltage output device, both the input and output terminals are characterized by low impedance. OTRA being a current mode building block inherits the advantages of current mode processing, the input terminals are virtually grounded leading to circuits that are insensitive to stray capacitances. Being a current processing device the OTRA has a bandwidth independent of the device gain and is also not slew limited in the same manner as an OP-AMP. Oscillators are used in various types of applications for these applications low value of total harmonic distortion (THD) is an essential requirement as higher harmonics have detrimental effects on electrical equipment The objective of the project is to design circuits of various types of oscillators i.e., Quadrature oscillator,wein bridge oscillator, sinusoidal oscillator using allpass section using Operational Transresistance Amplifier and studying THD analysis and simulate their MOS-C equivalent circuits for minimizing the chip area and for making these circuits electronically tuneable. These OTRA based designs are best suited for the Low Power and High Speed applications and Low Power Medical Devices apart from its traditional field of application i.e. Process Industry.