A 45 nm 2-port 8T-SRAM using hierarchical replica bitline technique with immunity from simultaneous R/W access issues

Satoshi Ishikura*, Marefusa Kurumada, Toshio Terano, Yoshinobu Yamagami, Naoki Kotani, Katsuji Satomi, Koji Nii, Makoto Yabuuchi, Yasumasa Tsukamoto, Shigeki Ohbayashi, Toshiyuki Oashi, Hiroshi Makino, Hirofumi Shinohara, Hironori Akamatsu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)

Abstract

We propose a new -port SRAM with a single read bit line (SRBL) eight transistors (8T) memory cell for a 45 nm system-on-a-chip (SoC). Access time tends to be slower as a fabrication is scaled down because of threshold voltage (Vt) random variations. A Divided read Bit line scheme with Shared local Amplifier (DBSA) realizes fast access time without increasing area penalty. We also show an additional important issue of a simultaneous Read and Write (RAV) access at the same row by using DBSA with the SRBL-8T cell. A rise of the storage node causes misreading. A Read End detecting Replica circuit (RER) and a Local read bit line Dummy Capacitance (LDC) are introduced to solve this issue. A 128 bit lines - 512 word lines 64 kb 2-port SRAM macro using these schemes was fabricated by a 45 nm bulk CMOS low-standby-power (LSTP) CMOS process technology [1]. The memory cell size is 0.597 μm3, This 2-port SRAM macro achieves 7 times faster access time without misreading.

Original languageEnglish
Pages (from-to)938-943
Number of pages6
JournalIEEE Journal of Solid-State Circuits
Volume43
Issue number4
DOIs
Publication statusPublished - 2008 Jan
Externally publishedYes

Keywords

  • 2-port SRAM
  • 8T cell
  • Hierarchical bit line
  • Misread
  • Simultaneous read/ write access
  • Single bit line

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

Fingerprint

Dive into the research topics of 'A 45 nm 2-port 8T-SRAM using hierarchical replica bitline technique with immunity from simultaneous R/W access issues'. Together they form a unique fingerprint.

Cite this