Arithmetic Logic Unit based on all-spin logic devices

Abstract

Spintronic devices have the potential to lower the power consumption of computing architectures such as Arithmetic Logic Units (ALUs). However, the existing spintronic ALUs still rely on charge current, which doesn't allow exploiting the spin devices properties for information transmission. All Spin Logic (ASL) devices based circuits have the potential to further improve these circuits and systems since they rely on pure spin current. Indeed, it has been shown that ASL-based circuits can be reconfigured through modification of the injection current polarity and the states of the control terminals. In this paper, for the first time, we propose two one-bit ALUs implemented using ASL devices. The first ALU is designed by the assembly of logic circuits while the second ALU is synthesized using majority gate method. SPICE simulations have been carried out with 40 nm diameter MTJ and the ALUs are compared regarding energy consumption and the number of ASL devices metrics. Comparison results show that the ALU designed using a majority gate based synthesis method consumes more energy than the logic circuit based ALU (1.917 vs. 0.486 nJ) but is easier to control.