Useful Skew Trade-offs · sta

Part 8 · ECO and Closure · All levels

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Skew is usually something to minimise, but it can also be used: delaying the capture clock of a flop gives time to the stage before it at the expense of the stage after it. Total slack around the flop is conserved; useful skew moves it. This topic covers the idea, the budget arithmetic across a pipeline, the side effects of building skew into a clock tree, and the sign-off of a skewed design.

Lesson	After it you can...
Skew as a Resource	Compute the feasible skew window for one flop.
Skew Budget Arithmetic	Distribute slack along a pipeline.
Clock Tree Side Effects	Account for variation and quantisation.
Signing Off Useful Skew	Check a skew across corners.

Check yourself What does delaying a flop's clock do to the stage before it and the stage after it?

It gives the stage before it more time for setup (but less hold margin) and gives the stage after it less time for setup (but more hold margin).

Up nextSkew as a Resource

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