BeginnerQuestion 7 of 40Source PDF page 10

What is data arrival time?

From PDVerse STA Mentor Guide · pdVerse Mentor Guide

Short Answer

Data arrival time is when a signal actually reaches a given node, computed by adding up all the delays along the path leading to it.

Example

If a flip-flop's clock-to-output delay is 95 ps and the data then takes 820 ps to travel through combinational logic to the next flop, the data arrival time at that endpoint is 0 + 95 + 820 = 915 ps. LAUNCH FF combinational logic CAPTURE FF CLK CLK

Why It Matters

Arrival time is one half of every timing check — it's compared against the required time to compute slack, so you cannot determine whether a path passes or fails without first knowing when the data actually gets there.

Equation

data arrival = launch clock + CK->Q + data delay = 0 + 95 + 820 =

Mentor Note — Common Mistake

Forgetting to include the launching flip-flop's own clock-to-output delay (CK->Q) when calculating arrival time, and only counting the combinational logic delay.

Visual explanationSTA context: What is data arrival time?
STA context: What is data arrival time?A three-step concept map summarizes the focus, core answer, and practical verification for What is data arrival time?Question focusWhat is data arrivaltime?Core answerData arrival time iswhen a signal actuallyreaches a given node,…Verify in practiceConfirm the path,constraints, clockassumptions, and timingreport.Understand → explain the mechanism → verify the assumptions

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