Variation
Variation models how process, voltage, temperature, and local effects change delay across chips and within one chip.
Signoff must account for correlated and uncorrelated variation without applying pessimism blindly.
AOCV varies derate by path depth and distance, avoiding the single worst-case multiplier used by simple OCV.
Static Timing Analysis flow
Follow each stage in sequence. Every stage produces information needed by the next.
Variation—visualized
This technical view uses the actual structures and relationships associated with this stage, followed by its key terms.
Understand every concept
PVT corners
What it is: PVT corners is a core concept within Variation. It describes the information, structure, or analysis engineers use at this stage of the Static Timing Analysis flow.
Why it matters: Understanding it helps you interpret the stage correctly, avoid incorrect assumptions, and connect the result to the next implementation or signoff step.
Where it fits: This topic belongs to module 3, Variation, and its output supports the stages that follow.
Practical example: Engineer workflow: Choose analysis corners for setup and hold. AOCV varies derate by path depth and distance, avoiding the single worst-case multiplier used by simple OCV.
OCV, AOCV and POCV
What it is: OCV, AOCV and POCV is a core concept within Variation. It describes the information, structure, or analysis engineers use at this stage of the Static Timing Analysis flow.
Why it matters: Understanding it helps you interpret the stage correctly, avoid incorrect assumptions, and connect the result to the next implementation or signoff step.
Where it fits: This topic belongs to module 3, Variation, and its output supports the stages that follow.
Practical example: Engineer workflow: Apply OCV, AOCV, or POCV derates. AOCV varies derate by path depth and distance, avoiding the single worst-case multiplier used by simple OCV.
Clock reconvergence pessimism
What it is: Clock reconvergence pessimism is a core concept within Variation. It describes the information, structure, or analysis engineers use at this stage of the Static Timing Analysis flow.
Why it matters: Understanding it helps you interpret the stage correctly, avoid incorrect assumptions, and connect the result to the next implementation or signoff step.
Where it fits: This topic belongs to module 3, Variation, and its output supports the stages that follow.
Practical example: Engineer workflow: Enable common-path pessimism removal where supported. AOCV varies derate by path depth and distance, avoiding the single worst-case multiplier used by simple OCV.
Work through it step by step
- 1
PVT corners
Choose analysis corners for setup and hold.
- 2
OCV, AOCV and POCV
Apply OCV, AOCV, or POCV derates.
- 3
Clock reconvergence pessimism
Enable common-path pessimism removal where supported.
- 4
PVT corners
Compare graph-based and path-based results on critical paths.
Explore each topic
01PVT corners
Understand the concept, connect it to the ASIC flow, study the report or behavior it produces, and apply it in a guided exercise. Check the result against the module goal before moving forward.
02OCV, AOCV and POCV
Understand the concept, connect it to the ASIC flow, study the report or behavior it produces, and apply it in a guided exercise. Check the result against the module goal before moving forward.
03Clock reconvergence pessimism
Understand the concept, connect it to the ASIC flow, study the report or behavior it produces, and apply it in a guided exercise. Check the result against the module goal before moving forward.
Completion checklist
- ✓ Derate tables match the process kit
- ✓ RC corner pairing is valid
- ✓ CPPR is understood
- ✓ PBA use is documented
Practise with open-source tools
These are official third-party GitHub projects selected for this learning path.