Spintronic Threshold Logic Array (STLA) - a compact, low leakage, non-volatile gate array architecture

Abstract

This paper describes a novel, first of its kind architecture for a threshold logic gate using conventional MOSFETs and an STT-MTJ (Spin Torque Transfer-Magnetic Tunnelling Junction) device. The resulting cell, called STL which is extremely compact can be programmed to realize a large number of threshold functions, many of which would require a multilevel network of conventional CMOS logic gates. Next, we describe a novel array architecture consisting of STL cells onto which complex logic networks can be mapped. The resulting array, called STLA has several advantages not available with conventional logic. This type of logic (1) is non-volatile, (2) is structurally regular and operates like DRAM, (3) is fully observable and controllable, (4) has zero standby power. These advantages are demonstrated by implementing a 16-bit carry look-ahead adder and compared with two optimized conventional FPGA implementations (Carry Look Ahead Adder and Ripple Carry Adder). The STLA has 12X lower transistor count (compared to CLA-FPGA) and 10X reduction (compared to RCA-FPGA) with comparable energy which will continue to reduce as the STT-MTJ device technology matures.