An accurate low iteration algorithm for effective capacitance computation

This paper presents an efficient and accurate approach to calculate effective capacitances in the presence of RC interconnect loads. In the pre-characterization process, the gate model is selected such that the output of the model matches both the delay and the shape of the real gate response. In order to determine the effective capacitance, a novel algorithm is developed to efficiently and accurately calculate the propagation delay from circuit elements. This algorithm requires at most two iterations to obtain effective capacitances that produce gate delays within 4% of HSPICE results. This is at most half the time required by the currently used method to calculate effective capacitances.

[1]  Alexander Korshak,et al.  An effective current source cell model for VDSM delay calculation , 2001, Proceedings of the IEEE 2001. 2nd International Symposium on Quality Electronic Design.

[2]  P. R. O'Brien,et al.  Modeling the driving-point characteristic of resistive interconnect for accurate delay estimation , 1989, ICCAD 1989.

[3]  Andrew B. Kahng,et al.  New efficient algorithms for computing effective capacitance , 1998, ISPD '98.

[4]  Lawrence T. Pileggi,et al.  Modeling the "Effective capacitance" for the RC interconnect of CMOS gates , 1994, IEEE Trans. Comput. Aided Des. Integr. Circuits Syst..

[5]  T. Sakurai,et al.  Approximation of wiring delay in MOSFET LSI , 1983, IEEE Journal of Solid-State Circuits.

[6]  R. Macys,et al.  A new algorithm for computing the "effective capacitance" in deep sub-micron circuits , 1998, Proceedings of the IEEE 1998 Custom Integrated Circuits Conference (Cat. No.98CH36143).

[7]  Li-Da Huang,et al.  Explicit gate delay model for timing evaluation , 2003, ISPD '03.

[8]  Jonathan Allen,et al.  Macromodeling CMOS circuits for timing simulation , 1988, IEEE Trans. Comput. Aided Des. Integr. Circuits Syst..

[9]  Lawrence T. Pileggi,et al.  Performance computation for precharacterized CMOS gates with RC loads , 1996, IEEE Trans. Comput. Aided Des. Integr. Circuits Syst..

[10]  Chirayu S. Amin,et al.  Computation of signal-threshold crossing times directly from higher order moments , 2004, IEEE Trans. Comput. Aided Des. Integr. Circuits Syst..