FR408HR & 370HR Backbones
Tg 180–200 °C low-loss FR-4 replacements for servers, storage, and telecom cards up to 25 G.
- Spread-glass to tame skew
- CAF mitigation templates
- Lead-free reflow ready
Materials
Isola High-Speed & RF PCB Manufacturing
We convert Isola laminates such as FR408HR, 370HR/185HR, Astra MT77, and I-Speed/I-Tera into tuned stackups for 10–56+ Gbps designs. Our guidance is backed by RayPCB projects and Isola datasheets, covering glass style, copper roughness, hybrid PTFE transitions, and reliability evidence.
Get an Instant Quote
Where Isola Materials Fit
Astra MT77 RF Control
Df 0.0017 and Dk 3.0 keep RF/microwave stages stable while remaining process-friendly.
- Hybrid with PTFE or FR-4
- Low PIM plating recommendations
- Bondply map to PTFE cores
I-Speed / I-Tera High-Speed
Df ~0.003 supports 25–56 G lanes, PCIe Gen5, and SERDES fabrics at lower cost than ultra-low-loss PTFE.
- VLP copper spec log
- COM/eye acceptance workflow
- Backdrill + VIPPO guidelines
Isola Laminates on Our AVL
| Series | Dk / Df @10 GHz | Primary Use |
|---|---|---|
| FR408HR | Dk 3.66 / Df 0.009 | Low-loss FR-4 for server and storage boards |
| 370HR / 185HR | Dk 3.8 / 3.6 • Df 0.015 / 0.012 | High-Tg multifunctional cores |
| Astra MT77 | Dk 3.0 / Df 0.0017 | RF/microwave control layers |
| I-Speed / I-Tera MT40 | Dk 3.4–3.45 / Df 0.0031–0.0037 | 25–56 G SerDes and network cards |
| Terra/IS680 (optional) | Dk 3.0 / Df 0.0025 | Cost-effective low-loss builds |
Key Isola Properties
| Material | Dielectric Constant | Dissipation Factor | Notes |
|---|---|---|---|
| FR408HR (0.014 in) | 3.66 @1 MHz | 0.009 | Baseline low-loss FR-4 |
| 370HR (0.012 in) | 3.80 | 0.015 | High-Tg multifunctional resin |
| Astra MT77 (0.010 in) | 3.00 @10 GHz | 0.0017 | Microwave-focused laminate |
| I-Tera MT40 (0.008 in) | 3.45 | 0.0031 | 56 G ready low-loss FR-4 |
| TerraGreen 400G (0.008 in) | 3.25 | 0.0024 | Mid-range ultra-low-loss option |
Values from Isola datasheets mirrored inside RayPCB archives; confirm actual lots for solver accuracy.
Isola Stackup Examples
12-Layer FR408HR Server Board
FR408HR signal layers with spread glass, FR-4 planes, and VIPPO connectors.
- Glass style (1035/2116) documented
- Backdrill ±3 mil control
- Impedance coupons ±5%
8-Layer Astra MT77 RF Section
Astra MT77 microstrip layers hybridized with FR-4 control and PTFE bondply.
- Hybrid plan with PTFE transitions
- Selective ENIG for RF pads
- VNA/TDR data pack
10-Layer I-Speed Backplane
I-Speed signal layers plus FR408HR planes for 28–56 G SerDes fabrics.
- 3/3 mil LDI imaging
- VIPPO fill plan included
- COM/eye summary provided
Isola Manufacturing Controls
Prebake & Storage
All Isola cores/prepregs baked at 120 °C / 2–4 h and stored <35% RH to prevent moisture spikes.
- Bake logs attached
- Vacuum packaging for shipment
- Moisture indicator cards
Copper Roughness & Etch
VLP/HVLP foil usage logged with Ra/Rz plus micro-etch removal for solver correlation.
- Ra/Rz certificates scanned
- Micro-etch depth ±0.2 µm
- Huray coefficients shared
Backdrill & VIPPO Control
Backdrill residual, VIPPO fill/planarity, and reference planes recorded for SerDes compliance.
- Residual <8 mil typical
- Planarity SPC ±0.5 mil
- Reference plane diagrams
Reliability Evidence
IST, CAF, and TDR/VNA overlays delivered, matching Isola application guideline requirements.
- IST >1000 cycles when specified
- CAF coupon results attached
- Environmental (-40↔125 °C) optional
Application Snapshots
Data Center Servers
FR408HR/370HR boards for compute and storage motherboards.
- Lead-free reflow proof
- Press-fit connector data
- AOI + flying probe coverage
Telecom & RF
Astra MT77 and I-Speed hybrids for radios and optical line cards.
- Hybrid plan with PTFE
- Selective finish for RF pads
- ESS logs per lot
Industrial / Aerospace
185HR + Thermount builds for rugged controllers and instrumentation.
- Conformal coat compatibility
- Thermal cycling results
- Traceability package
Isola Stack Selection Prompts
Inputs gathered before we freeze Isola material choices.
Performance window
Loss, Dk, and bandwidth to determine FR408HR vs I-Speed vs Astra.
- Lane speed/length
- RF vs digital mix
Hybrid plan
If mixing Isola with PTFE or Megtron, define bondply and plane splits.
- Bondply/adhesive
- Plane split diagrams
Validation scope
Agree on TDR/VNA, COM, CAF/IST, and ESS deliverables.
- Coupon placements
- Required reports
Isola PCB FAQ
Which Isola laminates do you stock?
FR408HR, 370HR/185HR, Astra MT77, I-Speed, and I-Tera MT40 cores/prepregs are stocked in common thicknesses; other series (IS680, TerraGreen) can be expedited.
How do you document glass and copper data?
Each stackup includes layer-by-layer glass style, copper weight, foil roughness, and micro-etch data for solver correlation.
Can Isola be hybridized with PTFE or Megtron?
Yes. We mix Isola cores with PTFE or Megtron using compatible bondply and track press cycles plus CTE alignment to avoid warpage.