Logical Effort Model Extension to Propagation Delay Representation - LIRMM - Laboratoire d’Informatique, de Robotique et de Microélectronique de Montpellier
Journal Articles IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Year : 2006

Logical Effort Model Extension to Propagation Delay Representation

Abstract

The logical effort method is widely recognized as a pedagogical way allowing designers to quickly estimate and optimize single paths by modeling equivalently propagation delay and transition time. However, this method necessitates a calibration of all the gates of the library and appears suboptimal in real combinatorial paths for satisfying tight timing constraints. This is due to the inability of the logical effort model in capturing I/O coupling and input ramp effects that distinguish the transition time from the propagation delay. Using an analytical modeling of the supply current that flows in simple gates during their switching process, this paper introduces an extension of the logical effort model that considers the I/O coupling capacitance and the input ramp effect. Validation of this model is performed on 130-nm STMicroelectronics technology. A compact representation of CMOS library timing performance is given as a possible application of the proposed model. The choice of sampling points to be used in look-up tables as representative steps of the design range is also discussed
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Dates and versions

lirmm-00104315 , version 1 (06-10-2006)

Identifiers

Cite

Benoit Lasbouygues, Sylvain Engels, Robin P. Wilson, Philippe Maurine, Nadine Azemard, et al.. Logical Effort Model Extension to Propagation Delay Representation. IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2006, 25 (9), pp.1677-1684. ⟨10.1109/TCAD.2005.857400⟩. ⟨lirmm-00104315⟩
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