E1 Demo First-Article Current-Limit Draft

Status: draft local bring-up plan, not first-article evidence Board revision: r0-nonrelease Review date: 2026-05-18 Reviewer: local board bring-up preflight Disposition: blocked for fabrication release

Scope

This document defines local current-limit starting points and stop conditions for first power application. It is not a measured current log and does not release the board for fabrication or bring-up.

Initial Bench Limits

Rail	Initial current limit	Initial voltage	Enable condition
1.8 V core/planning rail	25 mA	1.8 V	Enable first with SoC held in reset
3.3 V IO/planning rail	25 mA	3.3 V	Enable after 1.8 V rail is stable

The 25 mA starting point is a conservative lab limit, not an expected operating current. It is tied to the local OpenLane-only VDDCORE estimate in pd/signoff/pdn-current/local-budget.yaml and must be replaced before hardware execution by a board-revision-specific procedure. After shorts and static current are reviewed, limits may be raised only by an approved first-article procedure tied to the final board revision, regulator behavior, fuse limits, package load model, and thermal stop conditions.

Stop Conditions

• Any rail reaches current limit before the target voltage is within 5 percent.
• Any rail draws more than 2x the expected static current after reset is held.
• Rail monotonicity, sequencing, or reset behavior differs from the approved bring-up procedure.
• SoC package, PMIC, oscillator, regulator, or passives show abnormal heating.
• Clock, reset, or debug link is absent after rails are stable.

Release Blockers

• No measured first-article current log is archived.
• No final rail current budget exists for the selected padframe/package.
• No thermal limit or package power model is approved.
• No regulator current-limit tolerance or foldback behavior is signed off.
• No sustained power/thermal capture manifest has passed benchmarks/power/scripts/check_sustained_run_evidence.py.
• No bring-up owner has accepted these limits for hardware execution.

Required Release Evidence

• Final rail current budget with expected static, reset, debug-active, and NPU smoke-test currents.
• Lab current log for each rail, including supply model, limit settings, voltage ramp, ambient temperature, and board serial number.
• Sustained power/thermal manifest with calibrated power, thermal, frequency, workload transcript, and calibration artifacts.
• Explicit stop-condition review and first-article disposition.
• Updated limit table replacing this draft before any hardware power-on.