High Frequency Low Voltage CMOS Current Feedback Operational Amplifier Based Analog Building Blocks

Abstract

Analog integrated circuit design has reached to an advanced stage of circuit pattern by mixing of analog and digital functions on single chip. Merging both the functions on the same chip has led to the higher component densities along with the need of smaller device geometries, which in turn require low-voltage and low power operation of the devices. Traditionally analog circuits dominated by the voltage-mode circuits get severely affected by the reduction in power supply voltages. In current mode circuits, the signals are represented by flowing of the currents in branches so the performance of the current-mode circuits are less affected when power supply is reduced as compared to their counterparts. An important building block of current-mode circuit is current feedback operational amplifier. In this dissertation, high frequency low voltage CMOS current feedback operational amplifier (HFLVCFOA) and positive second generation current conveyor (CCII+) circuits are proposed. The CFOA is developed by cascading of the proposed CCII+ and a voltage buffer circuit. Analog building blocks like notch filter, frequency dependent negative resistor (FDNR) and inductor circuits are developed as the applications of the proposed CFOA. The proposed circuits are simulated in UMC 0.18μm CMOS process technology parameters. The layout of the proposed CFOA is designed using Cadence Virtuoso XL layout editor. The performance parameters of proposed CFOA and CCII has also been compared with the existing circuits available in the literature and the comparison shows that proposed CFOA has high gain bandwidth product and proposed CCII has wide input current linearity.