Design of an energy-efficient 2T-2MTJ nonvolatile TCAM based on a parallel-serial-combined search scheme

Shoun Matsunaga, Akira Mochizuki, Tetsuo Endoh, Hideo Ohno, Takahiro Hanyu

Research output: Contribution to journalLetterpeer-review

10 Citations (Scopus)


A parallel-serial-combined search scheme, which performs a multi-bit-by-multi-bit parallel-serial search for a single search, is proposed for a magnetic tunnel junction (MTJ)-based high-density and energy-efficient nonvolatile ternary content-addressable memory (TCAM). A two transistor and two MTJ device (2T-2MTJ)-based TCAM cell circuit can be utilized for a bit-parallel search operation up to 4 bits under random variations of MOS and MTJ device characteristics by amplifying the multi-bit cell-array resistance difference owing to the source-degeneration cell structure in combination with the cascode structure of the pre-amplification stage in the word circuit. In the proposed parallel-serial-combined search scheme, the bit length of a parallel operation in a single cycle and the search cycle count are optimized, so that the cell activity is minimized by tuning the trade-off between power consumption and search speed. When the proposed nonvolatile TCAM performs a variable-bit parallel-serial-combined search, the cell activity of the proposed nonvolatile TCAM is reduced to 60% of that of a conventional bit-parallel nonvolatile TCAM with a three-level segmentation scheme, which indicates higher density and higher energy efficiency with acceptable search speed.

Original languageEnglish
Article number20131006
JournalIEICE Electronics Express
Issue number3
Publication statusPublished - 2014 Jan 15


  • Associative memory
  • Power gating
  • Resistive
  • STT
  • Spintronics

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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