Spin-Torque Sensors for Energy Efficient High Speed Long Interconnects

TL;DR

This paper introduces a spin-torque based sensing scheme for energy-efficient, high-speed, long-distance interconnects that outperform traditional charge-based methods in energy consumption and speed.

Contribution

It proposes a novel spin-torque sensing architecture using Magnetic Tunnel Junctions and Spin-Hall Metal, eliminating the need for analog transceivers and enabling multi-bit high-speed operation.

Findings

Energy consumption of 3.93-4.72 fJ/bit/mm at 1-2 Gbits/sec

High-speed operation with simple digital components

Further energy reduction with Voltage Controlled Magnetic Anisotropy

Abstract

In this paper, we propose a Spin-Torque (ST) based sensing scheme that can enable energy efficient multi-bit long distance interconnect architectures. Current-mode interconnects have recently been proposed to overcome the performance degradations associated with conventional voltage mode Copper (Cu) interconnects. However, the performance of current mode interconnects are limited by analog current sensing transceivers and equalization circuits. As a solution, we propose the use of ST based receivers that use Magnetic Tunnel Junctions (MTJ) and simple digital components for current-to-voltage conversion and do not require analog transceivers. We incorporate Spin-Hall Metal (SHM) in our design to achieve high speed sensing. We show both single and multi-bit operations that reveal major benefits at higher speeds. Our simulation results show that the proposed technique consumes only 3.93-4.72 fJ/bit/mm energy while operating at 1-2 Gbits/sec; which is considerably better than existing charge based interconnects. In addition, Voltage Controlled Magnetic Anisotropy (VCMA) can reduce the required current at the sensor. With the inclusion of VCMA, the energy consumption can be further reduced to 2.02-4.02 fJ/bit/mm