Design of Low power four function 8-bit ALU for nano based systems

An arithmetic logic unit (ALU) is a digital circuit that performs arithmetic and bitwise logical operations on integer binary numbers. The ALU is the core of a CPU in a computer. The ALU receives the information from the registers and performs a given operation as specifies by the control. In contrast to a floating-point unit (FPU), which is a digital circuit that operates on floating point numbers with the aid of one or more internal ALUs. Powerful and complex ALUs are mostly utilized in modern, high performance CPUs, FPUs and graphics processing units (GPUs). Thus there is a pressing need to develop high speed and lower power consumed ALU. Single electron transistor (SET) is a high speed nano device and its controlled tunneling ability makes it high operating speed and its small size leads to low power consumption. In this paper, a four function 8-bit ALU is designed that performs four functions `and´, `or´, `add´ and `sub´. This 8-bit ALU is designed using single electron transistor using SPICE software and compared with conventional CMOS. Based on the results obtained, it is proved that the single electron 8-bit ALU consumes much less power compared to the CMOS technology.