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  3. AR# 54071: 14.x Timing Analysis - Why does UG612 state that the hold analysis on Register-to-Register paths will be impacted by Clock Uncertainty?

AR# 54071

14.x Timing Analysis - Why does UG612 state that the hold analysis on Register-to-Register paths will be impacted by Clock Uncertainty?

Description

Why does UG612 (Figure 3-5)state that the hold analysis on Register-to-Register paths will be impacted by Clock Uncertainty?

Solution

The "Input Example" figure is correct and the hold analysis is impacted by Clock Uncertainty.

The "Register-to-Register" figure is incorrect since it implies that these registers are sharing the same BUFG/BUFR/BUFIO component. When two synchronous elements are sharing the same clock network, then the hold analysis is not impacted by the Clock Uncertainty. If the two synchronous elements do not share the same clock network, then the Clock Uncertainty will impact the hold analysis.

AR# 54071
Date 01/31/2013
Status Active
Type General Article
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