What is this Evidence Pack? This Evidence Pack links project requirements, compiler checks, generated artifacts, and release metadata into a static audit trail.
What was verified? The pack verifies that selected electrical, footprint, routing, and release checks were executed during the build.
How is tampering detected? SHA-256 cryptographic hashes / checksums are used to detect unexpected changes in compiled templates and evidence metadata. If a signing key is added later, the pack can be extended with digital signatures.
01 / DESIGN CONTEXT Design Intent
This case study serves as the Reference Implementation for OmeraCode's evidence-driven hardware engineering methodology. It documents the design of a high-reliability, 3-phase brushless motor controller optimized for industrial actuator systems.
OBJECTIVE
Develop a compact, low-noise BLDC driver operating under continuous high-current thermal loads.
PHYSICAL CONSTRAINTS - — Nominal Input: 24V DC
- — Phase Current: 30A continuous
- — Peak Phase Current: 40A
- — Layout Stackup: 6-layer rigid
SAFETY & STANDARD GATES - — Safety: IEC 61800-5-1
- — Thermal: IPC-2152
- — Spacing: IPC-2221A
02 / INPUT COMPLIANCE Requirements Input
In our methodology, requirements are the source of design truth. The requirements for this controller are structured into the compiler database with formal IDs:
REQ-001
Controller board shall support 30A continuous current per phase output line.
SYSTEM-REQ-V1.2.pdf
REQ-002
Maximum copper temperature rise delta shall remain below 20°C above ambient temperature.
THERMAL-SPEC-V1.2.pdf
REQ-003
Minimum electrical trace clearance limits between motor power phases and inputs shall satisfy IPC-2221A guidelines.
CLEARANCE-SPEC-V2.pdf
03 / TRACEABILITY SPINE Constraint Mapping
Instead of generating layouts directly from text, OmeraCode builds a traceable pathway from the input requirement to the geometric net. This mapping is the core architecture of the methodology:
TRACEABILITY MAPPING: net.MOTOR_PHASE_A
REQUIREMENT
REQ-001 30A Continuous Current
↓
CONSTRAINT
PARAM-004 Min trace width limit: 8.30 mm
↓
CALCULATION
CALC-2152 IPC-2152 Thermal Equation Solver
↓
VERIFICATION
VERIFY-008 PASS (Calculated rise: 14.8°C)
04 / MATH CALCULATIONS Calculation Records
Rather than presenting complex multi-line physical equations, the OmeraCode platform packages solver inputs and outputs in a structured table. This verifies that layout trace width and impedance values are mathematically closed.
NET:MOTOR_PHASE_A / B / C
INPUT:Load Current: 30A / Cu Weight: 2 oz / Max Temp Rise: 20°C
METHOD:IPC-2152 Internal Trace Solver
OUTPUT:Calculated width: 8.30 mm / Implemented width: 8.50 mm
RESULT:PASS (Calculated Temp Rise: 14.8°C)
NET:DIFF_FEEDBACK_90
INPUT:Target Impedance: 90 Ohm / Dielectric: FR-4 / Height: 4.5 mil
METHOD:IPC-2141 Differential Edge-Coupled Solver
OUTPUT:Calculated: 5.2 mil width, 6.0 mil spacing gap
RESULT:PASS (Impedance: 89.8 Ohm)
05 / PHYSICAL COMPLIANCE DRC Findings
The Design Rule Checker evaluates electrical and layout metrics. It reports passes and warnings. Warnings do not halt the process permanently, but they block compilation until resolved or overridden.
Rule Audited: Gate drive signal return path loop area.
Finding: Signal loop area of 14.2 mm² detected on Gate net `G_PHASE_A` (exceeds threshold budget target of 12.5 mm²).
Mitigation: Trace rerouted over Layer 2 ground reference plane to minimize inductance.
Rule Audited: Aspect ratio ring width check on high-density vias.
Finding: Annular rings audit: 0.15 mm width on 0.25 mm drill holes.
Mitigation: Meets IPC-6012 Class 3 structural requirements. No warning generated.
06 / HUMAN REVIEW GATE Design Review Log
The Design Review Log records exceptions and clearance overrides. It serves as proof that human authority remains active, documenting review comments and explicit decisions.
REVIEWER: Senior Hardware Engineer
FINDING: Phase A power net clearance insufficient (0.35 mm detected)
SEVERITY: HIGH
DECISION: Revision Required (Release Package Blocked)
RESOLUTION: Clearance spacing increased from 0.35 mm to 0.70 mm net-to-net to satisfy IPC-2221A Table 6.1 thresholds.
STATUS: ACCEPTED & SIGNED-OFF
07 / RETROSPECTIVE STUDY Lessons Learned
Building a physical motor driver board using OmeraCode highlighted several engineering friction points and demonstrated how the system enforces safety:
- [1] Thermal Margin Adjustment:
The targeted 30A current initially required an 8.30 mm copper width. At 1 oz copper default stackup, this trace width would have exceeded the board clearance boundaries. Moving to a selective 2 oz outer copper layer stackup resolved the width layout constraint.
- [2] Clearance Conflicts vs. Density:
Required isolation gaps between high-power motor phases and gate driver lines created conflicts in the compact board envelope. Routing high-speed feedback tracks internally on Layer 3 successfully isolated the crosstalk loops.
- [3] Human Review Intervention:
While the mathematical solver routed the nets within constraints, it initially positioned the phase lines close to the temperature sensor circuit. Human review flagged this potential heat induction coupling risk. Spacing was manually adjusted to isolate the sensor net.
- [4] Release Block on Verification Failure:
When the Phase A clearance exception was generated, compilation was immediately halted, blocking release packet generation until the override was signed off by the hardware release authority.
08 / FINGERPRINT MANIFEST Evidence Pack Export
Once release checklist criteria evaluate to true, the OmeraCode compiler bundles all files, logs, and checksums into an Evidence Pack (.epk archive):
PROJ-BLDC-40A.epk/
├── metadata.json # SHA-256 manifest hashes
├── requirements/
│ ├── specs.json # REQ-001 through REQ-003 schemas
│ └── trace_matrix.json # Net mapping connections
├── verification/
│ ├── solvers/
│ │ ├── SOLVER-2152-RUN.json
│ │ └── DIFF_FEEDBACK_90.json
│ ├── drc/
│ │ └── drc_report.json # DRC-014 and DRC-037 findings
│ └── reviews.json # Record-774 override approval history
├── release/
│ ├── gerber/ # Redacted layout and drill files
│ ├── schematic.pdf # Released schematic drawings
│ └── bom.csv # Sourcing bill of materials
└── signatures/
└── system_keys.sig # Cryptographic signature payload