A new very high output resistance FVF based class-A super-cascode CCII.

Second generation current conveyor (CCII) is a versatile fundamental building block that is used nowadays for designing of almost all kinds of current mode devises. A wide variety of CCII configuration offering diverse characteristics have been proposed in literature. However, not much effort has been put to improve the output resistance of this block. High output resistance is a very essential parameter that makes CCII a versatile block to be used in integrated circuits, without affecting its performance parameters. In this paper, an extensive survey has been carried out to explore high performance CCII topologies. Among these configurations flipped voltage follower (FVF) based class-A CCII architecture has been chosen because of its compact design, low voltage and current/voltage matching characteristics. Output resistance of this configuration has been increased by using super-cascode (SC) configuration and replacing the biasing circuitry by low voltage cascode current mirror. Small signal analysis of the proposed circuit has been carried out to mathematically validate the improvement achieved by this circuit. The proposed FVF based class-A SC-CCII offers very high output resistance while maintaining all the characteristics of FVF based class-A CCII. However, a small sacrifice has to be made in the required in supply voltage of the proposed design. The proposed CCII is simulated in LtSpice using 0.18 µm CMOS technology and is compared with various CCII configurations available in literature. The simulated results validate the high performance operation of the proposed SC-CCII and show that this block offers around 70 times increase in output resistance. The characteristic of this proposed SC-CCII makes it a versatile block to be used in wide applications with diverse characteristics. [ABSTRACT FROM AUTHOR]