loading...
 This Article 
   
 Share 
   
 Bibliographic References 
   
 Add to: 
 
Digg
Furl
Spurl
Blink
Simpy
Google
Del.icio.us
Y!MyWeb
 
 Search 
   
2006 IEEE International Workshop on Memory Technology, Design, and Testing (MTDT'06)
SRAM Cell Current in Low Leakage Design
Taipei, Taiwan
August 02-August 04
ISBN: 0-7695-2572-5
Ding-Ming Kwai, Intellectual Property Library Company Hsinchu, Taiwan
Ching-Hua Hsiao, National Chiao Tung University Hsinchu, Taiwan
Chung-Ping Kuo, Intellectual Property Library Company Hsinchu, Taiwan
Chi-Hsien Chuang, Intellectual Property Library Company Hsinchu, Taiwan
Min-Chung Hsu, Intellectual Property Library Company Hsinchu, Taiwan
Yi-Chun Chen, Intellectual Property Library Company Hsinchu, Taiwan
Yu-Ling Sung, Intellectual Property Library Company Hsinchu, Taiwan
Hsien-Yu Pan, Intellectual Property Library Company Hsinchu, Taiwan
Chia-Hsin Lee, Intellectual Property Library Company Hsinchu, Taiwan
Meng-Fan Chang, Intellectual Property Library Company Hsinchu, Taiwan
Yung-Fa Chou, National Tsing Hua University Hsinchu, Taiwan
This paper highlights the cell current characterization of a low leakage 6T SRAM by adjusting the threshold voltages of the transistors in the memory array to reduce the standby power. Experiments using a 0.25?m 2.5V standard CMOS process with and without the additional threshold voltage adjustment implant on a 1Mb test chip demonstrate the effectiveness. A substantial standby power reduction by an order of magnitude is achievable. However, it incurs a wider cell current variation, which is pronounced only at a lower supply voltage. As the supply voltage decreases, the percent deviation from the average value increases. This can be modeled by a simple powerlaw relationship. The result has important implications in both design and manufacturing of the low leakage SRAM. Comparing with the generic cell current without the additional threshold voltage adjustment, the crossover point of their percent deviations at 2V signifies two separate circuit strategies: operating at 1.5V requires larger sensing margin and operating at 2.5V enjoys better manufacturability. Hence, for the applications requiring low voltage operations, it favors a boosted supply voltage applied to a selected cell during the read access.
Citation:
Ding-Ming Kwai, Ching-Hua Hsiao, Chung-Ping Kuo, Chi-Hsien Chuang, Min-Chung Hsu, Yi-Chun Chen, Yu-Ling Sung, Hsien-Yu Pan, Chia-Hsin Lee, Meng-Fan Chang, Yung-Fa Chou, "SRAM Cell Current in Low Leakage Design," mtdt, pp.65-70, 2006 IEEE International Workshop on Memory Technology, Design, and Testing (MTDT'06), 2006
Usage of this product signifies your acceptance of the Terms of Use.