Signal-integrity timing

Signal-integrity timing is STA that accounts for the fact that a real on-chip signal isn't a clean, isolated pulse — it's a wiggling voltage on a wire surrounded by other switching wires, sagging power rails, and coupling capacitance. Plain STA treats each net in a vacuum; SI-aware STA adds back the messy reality: crosstalk that speeds or slows edges, supply noise that weakens drive, and glitches that can sneak through logic. It's the difference between timing a runner on an empty track versus in a crowded, jostling pack.

Practically, SI timing runs after detailed routing and parasitic extraction, when the tool finally knows which wires are physically neighbours and how strongly they couple. It iterates — because an aggressor's own timing window determines whether it can even hit a victim at the worst moment — and reports SI-adjusted slack alongside both delay degradation and noise (glitch) violations. As nodes shrink and wires crowd together, SI is no longer a corner-case afterthought but a first-class part of sign-off; ignoring it is how a chip passes 'clean' STA and still fails on silicon.