Row-by-Row Dynamic Source-Line Voltage Control (RRDSV) Scheme for Two Orders of Magnitude Leakage Current Reduction of Sub-1-V-VDD SRAM's

Kyeong-Sik MIN  Kouichi KANDA  Hiroshi KAWAGUCHI  Kenichi INAGAKI  Fayez Robert SALIBA  Hoon-Dae CHOI  Hyun-Young CHOI  Daejeong KIM  Dong Myong KIM  Takayasu SAKURAI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E88-C   No.4   pp.760-767
Publication Date: 2005/04/01
Online ISSN: 
DOI: 10.1093/ietele/e88-c.4.760
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic Circuits
Keyword: 
low-voltage SRAM,  low-power SRAM,  row-by-row,  low-leakage,  leakage reduction technique,  leakage suppression technique,  subthreshold current,  

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Summary: 
A new Row-by-Row Dynamic Source-Line Voltage Control (RRDSV) scheme is proposed to suppress leakage current by two orders of magnitude in the SRAM's for sub-70 nm process technology with sub-1-V VDD. This two-order leakage reduction is caused from the cooperation of reverse body-to-source biasing and Drain Induced Barrier Lowering (DIBL) effects. In addition, metal shields are proposed to be inserted between the cell nodes and the bit lines not to allow the cell nodes to be flipped by the external bit-line coupling noise in this paper. A test chip has been fabricated to verify the effectiveness of the RRDSV scheme with the metal shields by using 0.18-µm CMOS process. The retention voltages of SRAM's with the metal shields are measured to be improved by as much as 40-60 mV without losing the stored data compared to the SRAM's without the shields.