{"slug": "network-transformer-sample-evaluation-measurement-protocol-comparison-framework", "title": "Network Transformer Sample Evaluation: Measurement Protocol, Comparison Framework, and Sample-to-Production Checklist", "summary": "A developer published a structured protocol for evaluating network transformer samples before production commitment. The guide includes a sample request template, pre-solder measurement steps, functional tests, and a multi-source comparison matrix. The approach aims to catch footprint mismatches, OCL margin issues, and temperature risks early in the evaluation process.", "body_md": "Structured approach to requesting, measuring, and qualifying network transformer samples before production commitment.\n\nSample Request Specification Template\n\npythonSAMPLE_REQUEST = {\n\n# Required fields — specify ALL before contacting supplier\n\n\"speed_grade\": \"1000BASE-T\", # or \"10/100BASE-TX\"\n\n\"package\": \"SMD-16\", # SMD-8 / SMD-16 / THT\n\n\"poe_rating\": \"802.3at\", # None / 802.3af / 802.3at / 802.3bt\n\n\"temp_grade\": \"industrial\", # commercial (0/+70) or industrial (-40/+85)\n\n\"isolation_vac\": 1500, # V AC minimum; 4000 for medical 2MOPP\n\n\"quantity_pcs\": 10, # 5-20 for evaluation\n\n\"footprint_ref\": \"H1102NL-compatible\", # or None if no compatibility requirement\n\n```\n# Documents to request with samples\n\"required_docs\": [\n    \"Datasheet (latest revision)\",\n    \"OCL vs DC bias characterization (if PoE-rated)\",\n    \"Reflow profile (peak temp, ramp rate)\",\n    \"Reel/tape spec (carrier pocket dimensions)\",\n    \"RoHS/REACH compliance declaration\",\n    \"Application schematic / reference design\",\n]\n```\n\n}\n\nPre-Solder Measurement Protocol\n\npythonimport time\n\ndef pre_solder_evaluation(sample_id: str, speed_grade: str) -> dict:\n\n\"\"\"\n\nRun before soldering samples onto test PCB.\n\nReturns pass/fail dict with measured values.\n\n\"\"\"\n\nMIN_OCL = {\n\n\"10/100BASE-TX\": 350e-6, # 350 µH\n\n\"1000BASE-T\": 1000e-6, # 1000 µH\n\n}\n\n```\nresults = {}\n\n# 1. Dimensional check\nprint(f\"[{sample_id}] Step 1: Measure footprint vs. datasheet land pattern\")\nprint(\"  → Check: pin pitch, pad dimensions, body keepout\")\nprint(\"  → Mismatch here = redesign before production — catch it NOW\")\nresults[\"footprint_ok\"] = input(\"  Footprint matches? (y/n): \") == \"y\"\n\n# 2. OCL measurement\nprint(f\"\\n[{sample_id}] Step 2: OCL — LCR meter @ 100kHz / 0.1V RMS / 0A bias\")\nocl_measured = float(input(\"  Measured OCL (µH): \")) * 1e-6\nocl_min = MIN_OCL[speed_grade]\nresults[\"ocl_measured_uH\"] = ocl_measured * 1e6\nresults[\"ocl_pass\"] = ocl_measured >= ocl_min\nresults[\"ocl_margin_pct\"] = round((ocl_measured / ocl_min - 1) * 100, 1)\n\n# 3. DCR measurement\nprint(f\"\\n[{sample_id}] Step 3: DCR — 4-wire method, both windings\")\ndcr_pri = float(input(\"  DCR primary (Ω): \"))\ndcr_sec = float(input(\"  DCR secondary (Ω): \"))\nresults[\"dcr_primary_ohm\"] = dcr_pri\nresults[\"dcr_secondary_ohm\"] = dcr_sec\nresults[\"dcr_total_ohm\"] = round(dcr_pri + dcr_sec, 3)\n\n# 4. Hipot test\nprint(f\"\\n[{sample_id}] Step 4: Hipot — 1500V AC, 60 seconds\")\nresults[\"hipot_pass\"] = input(\"  Pass (zero breakdowns)? (y/n): \") == \"y\"\n\n# Summary\nresults[\"overall_pass\"] = all([\n    results[\"footprint_ok\"],\n    results[\"ocl_pass\"],\n    results[\"hipot_pass\"],\n])\n\nreturn results\n```\n\nFunctional Test Protocol\n\nAfter pre-solder checks PASS → solder onto test PCB, then:\n\nTest 1: Link establishment\n\nScope: Connect to GbE switch at rated speed (100M or 1G)\n\nPass: Link up within 5 sec, no auto-negotiate fallback\n\nTest 2: Traffic throughput (1 hour sustained)\n\nTool: iperf3 / RFC 2544 test\n\nPass: Zero packet errors, no link drops\n\nTest 3: Cable length sensitivity\n\nTest: 1m / 50m / 100m cable lengths\n\nPass: Stable link at all three lengths\n\nTest 4: PoE power delivery (if applicable)\n\nTest: Apply max rated current (350mA / 600mA / 960mA) for 30 min\n\nMeasure: Transformer temperature rise (IR camera or thermocouple)\n\nPass: Tj ≤ (rated Tmax − 15°C)\n\nTest 5: Temperature (industrial grade parts)\n\nTest: Repeat Test 1+2 at +70°C ambient\n\nPass: Link up and stable at temperature\n\nMulti-Source Comparison Matrix\n\npython# Record results from parallel supplier evaluation\n\nsources = {\n\n\"Supplier_A\": {\n\n\"part_no\": \"VT-GE100AT-SMD\",\n\n\"ocl_measured_uH\": 1150,\n\n\"ocl_margin_pct\": 15.0,\n\n\"dcr_pri\": 0.72,\n\n\"dcr_sec\": 0.68,\n\n\"hipot\": \"PASS\",\n\n\"link_1m\": \"PASS\", \"link_50m\": \"PASS\", \"link_100m\": \"PASS\",\n\n\"price_usd_per_pc\": 0.85,\n\n\"lead_time_days\": 7,\n\n\"moq\": 50,\n\n},\n\n\"Supplier_B\": {\n\n\"part_no\": \"HX-GBE-16P\",\n\n\"ocl_measured_uH\": 1010, # barely above 1000µH minimum\n\n\"ocl_margin_pct\": 1.0, # low margin — temperature risk\n\n\"dcr_pri\": 0.91,\n\n\"dcr_sec\": 0.88,\n\n\"hipot\": \"PASS\",\n\n\"link_1m\": \"PASS\", \"link_50m\": \"PASS\", \"link_100m\": \"FAIL\", # ← issue\n\n\"price_usd_per_pc\": 0.65,\n\n\"lead_time_days\": 14,\n\n\"moq\": 500,\n\n},\n\n}\n\nSample-to-Production Checklist\n\nWeek 1: [ ] Send complete sample request with spec sheet\n\n[ ] Receive samples + documentation package via DHL\n\nWeek 2: [ ] Dimensional check (footprint match)\n\n[ ] OCL / DCR / Hipot measurements on all samples\n\nWeek 3: [ ] Solder onto test PCB, functional tests 1-3\n\nWeek 4: [ ] PoE thermal test (if applicable), temperature test\n\nWeek 5: [ ] Compare multiple sources, select primary + alternate\n\nWeek 6: [ ] BOM update with approved part numbers\n\nWeek 7: [ ] Supplier qualification docs (ISO cert, CoC, test report)\n\nWeek 8+: [ ] First production order (confirm lead time for required quantity)\n\nVoohu Technology — [www.voohuele.com](http://www.voohuele.com)\n\nSamples from stock | MOQ 50pcs | DHL 3–5 days | Japan / Korea / SE Asia | OCL bias data included", "url": "https://wpnews.pro/news/network-transformer-sample-evaluation-measurement-protocol-comparison-framework", "canonical_source": "https://dev.to/mia_0da233d70fadc478964c1/network-transformer-sample-evaluation-measurement-protocol-comparison-framework-and-p1k", "published_at": "2026-07-14 08:56:31+00:00", "updated_at": "2026-07-14 09:00:15.528542+00:00", "lang": "en", "topics": ["developer-tools"], "entities": [], "alternates": {"html": "https://wpnews.pro/news/network-transformer-sample-evaluation-measurement-protocol-comparison-framework", "markdown": "https://wpnews.pro/news/network-transformer-sample-evaluation-measurement-protocol-comparison-framework.md", "text": "https://wpnews.pro/news/network-transformer-sample-evaluation-measurement-protocol-comparison-framework.txt", "jsonld": "https://wpnews.pro/news/network-transformer-sample-evaluation-measurement-protocol-comparison-framework.jsonld"}}