Quick & Efficient Extraction of Library Pessimism: Enabler for Faster Hold Timing Closure
TimeMonday, July 11th11:15am - 11:30am PDT
Location2008, Level 2
Event Type
Back-End Design
Engineering Tracks
Back-End Design
DescriptionLast mile hold timing closure has always been a challenge and ends up impacting schedule for complex SOCs. Hold violations are tricky to fix, as it can disturb the overall timing and create net routing issues due to several buffer additions in the design. Typically, pessimism exists in library hold-time requirement. In order to speed up overall timing closure, this work proposes a methodology to take benefit of pessimism in library and waive false violations at final stages and thereby fixing only the real ones. To find the extra margin present in library, Monte-Carlo (MC) simulation are run for each failing endpoint with the exact input signal slew values. This method becomes infeasible if the number of violations are large since it requires equal number of MC sims leading to huge overall runtime. This work proposes a methodology to reduce the number of MC sims by running the analysis only at limited signal slew condition on limited variants of failing cell type w.r.t drive strength and Vt. Some pessimism is traded off by this method in order to make this a practical solution for analyzing large number of violations.