Interpreting ENOB, SNDR, SFDR, INL, and DNL: Reports and Metrics

Reports and metrics

Reports and Metrics for Interpreting ENOB, SNDR, SFDR, INL, and DNL is anchored on noise/jitter/settling and integration stability across realistic corners and workloads. Convert observations into mechanism-backed and owner-bound actions.

A useful report explains why behavior moved, not only that behavior moved.

Evidence matrix

EVIDENCE MATRIX - Interpreting ENOB, SNDR, SFDR, INL, and DNL

+-----------------------------+--------------------------------+--------------------------------+---------------------------+
| Evidence                    | Tells you                      | Does not prove                 | Next action               |
+-----------------------------+--------------------------------+--------------------------------+---------------------------+
| setup calibration logs      | measurement chain validity     | mechanism root cause           | pair with transfer checks |
| spectrum and jitter plots   | frequency-domain behavior      | ownership of failure           | correlate with activity   |
| PVT corner overlays         | sensitivity distribution       | runtime workload equivalence   | add workload replay       |
| model-vs-silicon deltas     | assumption mismatch classes    | direct fix correctness         | test bounded mitigation   |
| before-after matrix         | mitigation movement            | long-term field drift          | run stress suites         |
+-----------------------------+--------------------------------+--------------------------------+---------------------------+

• Track noise/jitter/settling and integration stability across realistic corners and workloads on representative stress slices.

• Include setup, workload, and environmental metadata in every report.

• Correlate measured movement with source-path-victim assumptions.

• Call out contradictory evidence explicitly.

Analog deep dive

ADC success comes from aligning sampling assumptions, architecture constraints, and metric interpretation.

Concept diagram

ADC VALIDATION FLOW

front-end assumptions -> sampler behavior -> quantization path -> metric interpretation

Metric graph

ADC FAILURE MIX

aliasing leakage         ████
jitter-limited SNR       █████
metric misuse            ███

Metrics and artifacts to collect

• alias and blocker folding map

• clock-jitter impact estimate

• architecture throughput/latency fit

• ENOB/SNDR/SFDR context table

Mini case study

ENOB shortfall resolved after anti-alias assumptions and clock quality were corrected, without changing core quantizer logic.

Debug branches

• Verify coherent sampling and FFT setup before root-cause claims.

• Classify whether loss is noise, distortion, or folded interference.

• Audit architecture-fit assumptions against workload bandwidth.

Senior review question

Ask: which source-path-victim boundary failed first, and which artifact proves it reproducibly?

Key takeaways

• Tie every analog claim to one measurable metric and one proving artifact.

• Prefer minimal reversible mitigations with explicit owner and rollback criteria.

Common pitfalls

• Treating all noise as one scalar instead of path and frequency dependent behavior.

• Changing multiple analog knobs at once and losing causality.

• Declaring closure from nominal behavior without stress replay evidence.

Report interpretation

Treat report movement as hypothesis evidence, not final proof.

Cross-check metrics with setup integrity and model assumptions.