A 256b-wordlength ReRAM-based TCAM with 1ns search-time and 14× improvement in wordlength-energyefficiency-density product using 2.5T1R cell

Chien Chen Lin, Jui Yu Hung, Wen Zhang Lin, Chieh Pu Lo, Yen Ning Chiang, Hsiang Jen Tsai, Geng Hau Yang, Ya Chin King, Chrong Jung Lin, Tien-Fu Chen, Meng Fan Chang

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

36 Scopus citations

Abstract

Ternary content-addressable memory (TCAM) is used in search engines for network and big-data processing [1]-[6]. Nonvolatile TCAM (nvTCAM) was developed to reduce cell area (A), search energy (ES), and standby power beyond what can be achieved using SRAM-based TCAM (sTCAM) [1]-[2]: particularly in applications with long idle times and frequent-search-few-write operations. nvTCAMs were previously designed using diode-4T2R (D4T2R) with STT-MTJ [3], 2T2R with phase-change memory [4], 4T2R and 3T1R with ReRAM [5,6]. However, these NV devices suffer from the following issues: 1) High ES requirements due to cell-DC-current (IDC-CELL) as well as large match-line (ML) parasitic load (CML), particularly when word-length (WDL) is long; 2) Large A due to the use of two NVM (2R) devices [3]-[5] or in-cell control logic [6]; 3) Limited WDL caused by small ML current-ratio (IML-ratio ? IML-MIS/N∗IML-M) between mismatch current (IML-MIS) and the leakage-current (IML-M) from cells on a ML, particularly when NVM resistance (R)-ratio (=RHRS /RLRS) between high-R (HRS, RHRS) and low-R (LRS, RLRS) states is small due to process variation; 4) Long search delays (TSD) due to large CML and small IML-ratio. This work proposes 1) a 2.5T1R cell to reduce A, CML, and ES as well as increase IML-ratio; and 2) a region-splitter (RS) sense amplifier (SA) to achieve robust sensing with a smaller ML-Voltage (VML) swing (VMLS) to reduce TSD and ES.

Original languageEnglish
Title of host publication2016 IEEE International Solid-State Circuits Conference, ISSCC 2016
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages136-137
Number of pages2
ISBN (Electronic)9781467394666
DOIs
StatePublished - 23 Feb 2016
Event63rd IEEE International Solid-State Circuits Conference, ISSCC 2016 - San Francisco, United States
Duration: 31 Jan 20164 Feb 2016

Publication series

NameDigest of Technical Papers - IEEE International Solid-State Circuits Conference
Volume59
ISSN (Print)0193-6530

Conference

Conference63rd IEEE International Solid-State Circuits Conference, ISSCC 2016
CountryUnited States
CitySan Francisco
Period31/01/164/02/16

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