一种近阈值电压标准单元特征化建库方法
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摘要
面向近阈值电压下库单元的实际使用情况,针对传统库文件查找表误差较大的问题,提出了一种近阈值电压下对标准单元的特征化建库方法.通过对标准单元实际应用情况的分析,重新界定了查找表的边界;通过分析电路综合结果与电路仿真结果的相对误差,重新确定了查找表的规模;从而提高了近阈值电压下标准单元库准确性.该方法对smic55nmCMOS工艺的库文件在0.6 V电压下特征化建库,并进行误差评估,结果表明,该方法相较于传统方法建立的库文件,准确性提高了16%～63.51%,减小了查找表误差,有效提高了库文件的准确性.
According to the actual application of a standard library cell operating in the near-threshold voltage region,and due to the problem of large error in the lookup table of traditional library files,this paper proposed a method to characterize the standard cell in near-threshold voltage region. The method redefined the boundary of the lookup table by analyzing the actual application of standard cell in near-threshold voltage,and by analyzing the relative error between the circuit synthesis result and circuit simulation result,it re-determined the scale of the lookup table,in order to improve the accuracy of standard cell library in near-threshold voltage region. This method was then used to characterize the smic55 nmCMOS process library file in 0.6 V voltage and evaluate the relative error,and the results show that when compared with the library file established by traditional characterize method,the proposed method improved the library file's accuracy by 16%～63.51%,reduced the error of lookup table,and effectively improved the accuracy of library file.
According to the actual application of a standard library cell operating in the near-threshold voltage region,and due to the problem of large error in the lookup table of traditional library files,this paper proposed a method to characterize the standard cell in near-threshold voltage region. The method redefined the boundary of the lookup table by analyzing the actual application of standard cell in near-threshold voltage,and by analyzing the relative error between the circuit synthesis result and circuit simulation result,it re-determined the scale of the lookup table,in order to improve the accuracy of standard cell library in near-threshold voltage region. This method was then used to characterize the smic55 nmCMOS process library file in 0.6 V voltage and evaluate the relative error,and the results show that when compared with the library file established by traditional characterize method,the proposed method improved the library file's accuracy by 16%～63.51%,reduced the error of lookup table,and effectively improved the accuracy of library file.
引文
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[2]SYNOPYSYS.Siliconsmart User′s Guide:Version 2013.06[EB/OL].https://solvent,synopsys.com
[3]JUN J,SONG J,KIM C.A near-threshold voltage oriented digital cell library for high-energy efficiency and optimized performance in 65nm CMOS process[J].IEEE Transactions on Circuits and Systems I,2017,65(5):1567-1580.
[4]WEY I C,LIN P J,WU B C,et al.Near-threshold-voltage circuit design:The design challenges and chances[C]//International SoCDesign Conference(ISOCC).Jeju:IEEE,2014:138-141.
[5]袁甲,张苏敏,商新超,等.一种基于商用标准单元库的极低电压电路设计方法[J].微电子学与计算机,2014,31(12):6-9.YUAN J,ZHANG S M,SHANG X C,et al.An ultra voltage technique based on foundary standard cell libray[J].Microelectronics&Computer,2014,31(12):6-9.(In Chinese)
[6]JIANG J H,LIANG M,WANG L,et al.An effective timing characterization method for an accuracy-proved VLSI standard cell library[J].Journal of Semiconductors,2014,35(2):025005-1-025005-5.
[7]SYNOPSYS.Library Compiler User′s Guide:Version 2016.12[EB/OL].https://solvnet.synopsys.com
[8]CHARAFEDDINE K,OUARDI F.Fast timing characterization of cells in standard cell library design based on curve fitting[C]//2017 International Conference on Wireless Technologies,Embedded and Intelligent Systems(WITS).Fez:IEEE,2017:1-6.