Speedpath Analysis Under Parametric Timing Models

The clock frequency of a digital IC is limited by its slowest paths, designated by speedpaths. Given the extreme complexity involved in modeling modern IC technologies, often speedpath predictions provided by timing analysis tools are not correct. Therefore, several practical techniques have recently been proposed for design debugging, that combine silicon stepping of improved versions of a circuit with subsequent correlation between measured and predicted data. Addressing these issues, this paper proposes a set of techniques that enable the designer to obtain reduced subsets of paths, guaranteed to contain all the speedpaths of a given circuit or block. Such subsets can be computed either from timing models, prior to fabrication, or incorporating actual delay measurements from fabricated instances.