Quick Decision: IT-180A or 370HR?
| Criterion | ITEQ IT-180A | Isola 370HR | Winner |
|---|---|---|---|
| Tg (DSC) | 175C | 180C | 370HR |
| Td (5% weight loss) | 330C | 340C | 370HR |
| Dk at 1 GHz | 4.0 | 4.1 | IT-180A |
| Df at 1 GHz | 0.016 | 0.018 | IT-180A |
| CAF resistance | Good | Excellent | 370HR |
| Asia-Pacific availability | Excellent | Good | IT-180A |
| Cost premium vs std FR-4 | +15-25% | +25-40% | IT-180A |
The 30-second answer: Choose 370HR when CAF resistance and automotive qualification matter more than cost. Choose IT-180A when you need solid mid-Tg performance with better pricing and faster delivery from Asian fabricators.
Where These Laminates Fit in the Material Hierarchy
Both IT-180A and 370HR sit in the "enhanced FR-4" tier — above standard Tg 130-140C material but below true high-performance laminates like Megtron 6 or Isola I-Speed. Engineers reach for this tier when standard FR-4 fails thermal cycling requirements or when the design operates above 100C ambient, but the signal integrity budget does not justify premium low-loss materials.
The typical applications driving this material choice include automotive ECUs that must survive under-hood temperatures, industrial motor drives with sustained 85C operation, telecom infrastructure boards requiring 20-year field life, and medical devices needing IPC Class 3 reliability.
What makes this comparison particularly relevant in 2026 is the supply chain dynamic. ITEQ has significantly expanded its manufacturing capacity in Taiwan and mainland China, making IT-180A increasingly price-competitive for Asia-sourced fabrication. Meanwhile, Isola's 370HR remains the default specification at many North American and European OEMs.
Thermal Performance: The Numbers That Matter
The glass transition temperature (Tg) headline numbers — 175C for IT-180A versus 180C for 370HR — tell only part of the thermal story. More important for real-world reliability is the thermal decomposition temperature (Td), which indicates when the resin system begins irreversible degradation.
At Td 330C (IT-180A) versus 340C (370HR), the 10C difference provides 370HR with slightly more margin during lead-free reflow profiles that peak at 250-260C. In practice, both materials comfortably survive 6 reflow cycles per IPC-TM-650 testing.
The more meaningful thermal differentiator is the Z-axis coefficient of thermal expansion (CTE) above Tg. Both materials maintain excellent Z-CTE (2.7-2.8% total expansion from 50C to 260C), which directly correlates with plated through-hole reliability during thermal cycling. For comparison, standard FR-4 typically shows 3.5-4.5% Z-expansion over the same range.
For designs requiring IPC-6012 Class 3 performance, the 370HR's slightly lower Z-CTE provides a measurable margin. Internal IST (Interconnect Stress Test) data shows 370HR consistently passing 300+ cycles at -55C to +125C, while IT-180A achieves 250+ cycles.
Electrical Properties: Dk, Df, and What They Mean for Your Design
For controlled impedance designs operating below 3 GHz, both materials deliver adequate dielectric constant stability. IT-180A's slightly lower Dk (4.0 vs 4.1 at 1 GHz) means marginally wider traces for a given impedance target — typically 0.5-1.0 mil wider on inner layers.
The dissipation factor (Df) comparison is counterintuitive: IT-180A actually has lower loss (0.016 vs 0.018 at 1 GHz) despite being the lower-cost material. This 12% difference in Df translates to roughly 0.1 dB/inch less insertion loss at 5 GHz on a typical stripline configuration.
However, neither material should be your first choice for genuine high-speed applications above 10 Gbps NRZ. At those data rates, you need actual low-loss laminates (Df below 0.005) like Megtron 6 or Isola I-Speed.
CAF Resistance: The Hidden Reliability Factor
Conductive Anodic Filament (CAF) formation is a failure mechanism that receives insufficient attention during material selection. CAF occurs when copper ions migrate along the glass fiber/resin interface under bias voltage, eventually creating a conductive path between adjacent conductors.
Isola 370HR was specifically engineered with enhanced resin-to-glass adhesion to resist CAF formation. In standardized testing per IPC-TM-650 Method 2.6.25, 370HR demonstrates no failures at 100V bias, 85C/85%RH, for 1000+ hours at 0.3mm drill-to-drill spacing.
For designs operating at 48V or higher (EV battery management, power supplies, solar inverters), CAF resistance should be a primary material selection criterion. In these applications, the 370HR premium is justified by reduced field failure risk.
Supply Chain and Cost Considerations
The pricing differential varies significantly by region:
| Cost Factor | IT-180A (Asia fab) | 370HR (Asia fab) | 370HR (NA/EU fab) |
|---|---|---|---|
| Laminate cost per sqft | $8-12 | $12-16 | $14-18 |
| Per-board material (100x150mm, 8L) | $4-6 | $6-9 | $7-10 |
| Lead time impact | None | +5-7 days | None |
ITEQ's multiple manufacturing sites across Asia provide redundancy, while Isola's more concentrated production occasionally leads to allocation constraints during demand surges.
Decision Framework
Specify 370HR when:
- Automotive OEM qualification requires it
- Operating voltage exceeds 48V with fine-pitch vias (CAF risk)
- Design must meet MIL-PRF-31032 or IPC-6012 Class 3/A
- Thermal cycling range exceeds -40C to +125C for 1000+ cycles
Specify IT-180A when:
- Primary fabrication source is in Asia-Pacific
- Cost optimization is important without sacrificing mid-Tg reliability
- Design operates below 48V with standard via geometries
- Lead time is critical and local material availability matters
Both laminates are available through AtlasPCB with validated impedance models. Our engineering team helps match material grade to your specific thermal, electrical, and reliability requirements.
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