Robust High Speed Ternary Magnetic Content Addressable Memory

Designing robust, low power, and delay ternary magnetic content addressable memory (TMCAM) using spintronic-based devices like magnetic tunnel junction (MTJ) is a challenge. Process variations in MTJ and transistor degrade the performance of ternary content-addressable memory (TCAM) as the number of bits increases. To bring TCAM using MTJ (TMCAM) to practical use for wide arrays (>2048 bits), its cell has to be designed with large tolerance to all types of variations. Reducing the power consumption associated with searching without the increase in delay is also essential for the designing of TMCAMs. The proposed TMCAM cell has guaranteed read-disturbance immunity, low delay, and comparable power as compared with the reported MTJ-based magnetic-content-addressable memory (MCAM). Monte Carlo simulation was performed for proving the robustness of the proposed TMCAM by considering both variations in MTJ and transistor parameters. A Verilog-A model of the MTJ along with 45-nm CMOS technology is used for the simulation. A delay reduction of 1.23 times with power decrement of 1.23 times is obtained compared with previously reported MCAM for TMR = 3. This leads to a power-delay product improvement of 1.5 times for 2048-bit TMCAM.

[1]  Seung H. Kang,et al.  A 45nm 1Mb embedded STT-MRAM with design techniques to minimize read-disturbance , 2011, 2011 Symposium on VLSI Circuits - Digest of Technical Papers.

[2]  Hoi-Jun Yoo,et al.  A 0.7-fJ/bit/search 2.2-ns search time hybrid-type TCAM architecture , 2004, IEEE Journal of Solid-State Circuits.

[3]  Charles A. Zukowski,et al.  VLSI implementation of routing tables: tries and CAMs , 1991, IEEE INFCOM '91. The conference on Computer Communications. Tenth Annual Joint Comference of the IEEE Computer and Communications Societies Proceedings.

[4]  Jonathan Z. Sun Spin-current interaction with a monodomain magnetic body: A model study , 2000 .

[5]  Karl-Erwin Großpietsch,et al.  Associative processors and memories: a survey , 1992, IEEE Micro.

[6]  Weizhong Wang Magnetic Content Addressable Memory Design for Wide Array Structure , 2011, IEEE Transactions on Magnetics.

[7]  Eric Belhaire,et al.  New non‐volatile logic based on spin‐MTJ , 2008 .

[8]  Weizhong Wang Magnetic Random Accessible Memory Based Magnetic Content Addressable Memory Cell Design , 2010, IEEE Transactions on Magnetics.

[9]  Weisheng Zhao,et al.  Compact Modeling of Perpendicular-Anisotropy CoFeB/MgO Magnetic Tunnel Junctions , 2012, IEEE Transactions on Electron Devices.

[10]  Mamoru Nakanishi,et al.  On using the CAM concept for parametric curve extraction , 2000, IEEE Trans. Image Process..

[11]  Jacques-Olivier Klein,et al.  Failure and reliability analysis of STT-MRAM , 2012, Microelectron. Reliab..

[12]  Tetsuo Endoh,et al.  Design of a 270ps-access 7-transistor/2-magnetic-tunnel-junction cell circuit for a high-speed-search nonvolatile ternary content-addressable memory , 2012 .

[13]  A. Panchula,et al.  Magnetically engineered spintronic sensors and memory , 2003, Proc. IEEE.

[14]  Sethuraman Panchanathan,et al.  A content-addressable memory architecture for image coding using vector quantization , 1991, IEEE Trans. Signal Process..

[15]  Z. Diao,et al.  Spin-transfer torque switching in magnetic tunnel junctions and spin-transfer torque random access memory , 2007 .

[16]  Ali Sheikholeslami,et al.  A ternary content-addressable memory (TCAM) based on 4T static storage and including a current-race sensing scheme , 2003, IEEE J. Solid State Circuits.

[17]  A. Fert,et al.  The emergence of spin electronics in data storage. , 2007, Nature materials.

[18]  J. C. Sloncxewski Current-driven excitation of magnetic multilayers , 2003 .

[19]  H. Ohno,et al.  Tunnel magnetoresistance of 604% at 300K by suppression of Ta diffusion in CoFeB∕MgO∕CoFeB pseudo-spin-valves annealed at high temperature , 2008 .

[20]  Hyungsoon Shin,et al.  The 3-Bit Gray Counter Based on Magnetic-Tunnel-Junction Elements , 2007, IEEE Transactions on Magnetics.

[21]  Stuart A. Wolf,et al.  Spintronics : A Spin-Based Electronics Vision for the Future , 2009 .