Package Effects on AMS: Inputs & Outputs

Inputs and outputs contract

Inputs & Outputs for Package Effects on AMS focuses on package-induced jitter, return-path discontinuity flags, board bring-up instability. The goal is to connect observed symptom to boundary mechanism, ownership, and signoff risk.

Treat these inputs and outputs as signed interface guarantees. Ambiguity here creates the most expensive integration bugs.

INPUTS
  - AMS handoff contract and spec revision
  - mode definitions (power/clock/reset/traffic)
  - wrapper and boundary-cell assumptions
  - physical constraints: keepouts, guard, package limits

OUTPUTS
  - mode-tagged metric report
  - owner-signed debug or closure note
  - waiver manifest with expiry and controls
  - release recommendation

Boundary sequence

AMS BOUNDARY SEQUENCE — Package Effects on AMS

analog macro -> wrapper / boundary cell -> synchronizer or sampler -> digital consumer
      |                 |                         |                     |
  analog assumptions    legal voltage/state       clock/reset contract   protocol/data validity

metric under watch: package-induced jitter, return-path discontinuity flags, board bring-up instability

Ownership map

OWNERSHIP MAP — Package Effects on AMS

artifact                  owner
----------------------    -----------------------------
integration artifact    package engineer
implementation artifact board SI owner
signoff artifact        SerDes/PLL owner

Every boundary issue needs a named owner before fixes start.

AMS deep dive

AMS signoff is a combined noise, IR, timing, and package decision.

Concept diagram

BOUNDARY SIGNOFF

noise + IR + package + timing -> release decision

Metric graph

RISK DASHBOARD

open blockers █████
waivers       ███

Reports and artifacts

• supply ripple spectrum

• IR around analog islands

• package PI summary

• release dashboard

Mini case study

IR hotspot at analog island caused jitter spikes only under burst traffic.

Debug branches

• Correlate droop and jitter

• Check package return path

• Validate mode-specific activity profile

Senior review question

Ask: what boundary condition proves this topic is actually closed?

Key takeaways

• State boundary, mode, and evidence tag with every claim.

• Always align analog, digital, and physical owners before signoff decisions.

Common pitfalls

• Fixing averages while tails still fail.

• Skipping package/supply evidence in jitter or SerDes issues.

• Shipping with waivers that lack owner and expiration criteria.

Principal AMS review addendum

Bump assignments, return-current loops, and package resonances alter reference quality and high-speed channel behavior seen by mixed-signal interfaces.

Metric: package-induced jitter, return-path discontinuity flags, board bring-up instability