Path-RO: a novel on-chip critical path delay measurement under process variations

— As technology scales to 45nm and below, process variations will present significant impact on path delay. This trend makes the deviation between simulated path delay and actual path delay in a manufactured chip more significant. In this paper, we propose a new onchip path delay measurement structure called path-based ring oscillator (Path-RO). The proposed method creates an oscillator from a targeted path for which it is used to measure path delay on-chip under the impact of process variations. To alleviate accuracy degradation caused by the architecture itself, a high-accuracy calibration process is presented. Through experimental results on Path-ROs inserted in ITC’99 b19 benchmark, we obtain path delay distribution under different process variations. The accuracy and efficiency of path delay measurement using Path-RO are also verified by comparing the results obtained from postlayout Hspice simulations.

• Type: Conference
• Year: 2008
• Where: ICCAD
• Authors: Xiaoxiao Wang, Mohammad Tehranipoor, Ramyanshu Datta
• Keywords: Hardware, ICCAD 2008, Path Delay, Path Delay Measurement, Process Variations