Isola I-Tera MT40
Dk 3.45 | Df 0.0031 @ 10 GHz — the cost-effective sweet spot between standard high-Tg and ultra-low-loss materials for 25G–56G channels.
3.45
Dk @ 10 GHz
0.0031
Df @ 10 GHz
200°C
Tg (DSC)
360°C
Td
What Is Isola I-Tera MT40?
Isola I-Tera MT40 is a low-loss, E-glass reinforced laminate with a modified epoxy resin system that delivers a Df of 0.0031 at 10 GHz. It occupies the performance tier between standard high-Tg materials like 370HR and ultra-low-loss options like Astra MT77.
This positioning makes I-Tera MT40 the go-to choice for engineers who need better signal integrity than FR-4 but cannot justify the cost premium of ultra-low-loss laminates — particularly in volume networking and storage applications running 25G to 56G per lane.
Low-Loss Performance
Df 0.0031 provides ~40% less loss than standard high-Tg FR-4
Standard Processing
E-glass reinforcement enables conventional fabrication without exotic tooling
Robust Thermal Profile
200°C Tg and 360°C Td for demanding lead-free assembly environments
Material Properties
| Property | Value | Test Method |
|---|---|---|
| Dielectric Constant (Dk) | 3.45 ±0.05 | IPC-TM-650, 10 GHz |
| Dissipation Factor (Df) | 0.0031 | IPC-TM-650, 10 GHz |
| Glass Transition (Tg) | 200°C | DSC |
| Decomposition Temp (Td) | 360°C | TGA, 5% wt loss |
| CTE Z-axis | ~40 ppm/°C | TMA |
| Flammability | UL 94 V-0 | UL |
| Reinforcement | E-glass | — |
| Resin System | Modified epoxy | — |
Technical Highlights
56G NRZ / 25G PAM4
Supports up to 56 Gbps NRZ and 25G PAM4 SerDes with comfortable loss margin across 10–12 inch traces in typical switch linecards.
Cost-Optimized
E-glass construction uses standard fabrication processes, reducing per-panel cost 30–40% compared to spread-glass ultra-low-loss alternatives.
Proven Processability
Well-characterized drilling, plating, and lamination behavior makes I-Tera MT40 a low-risk choice for new designs migrating from standard FR-4.
I-Tera MT40 vs. Competing Materials
| Property | I-Tera MT40 | Isola 370HR | Astra MT77 |
|---|---|---|---|
| Dk @ 10 GHz | 3.45 | 3.92 | 3.00 |
| Df @ 10 GHz | 0.0031 | 0.005 | 0.0017 |
| Tg (°C) | 200 | 180 | 200 |
| Td (°C) | 360 | 340 | 360 |
| Relative Cost | $–$$ | $ | $$ |
I-Tera MT40 sits in the sweet spot — significantly better loss than 370HR with only a modest cost increase, making it the pragmatic choice for 25G–56G production designs.
Target Applications
Enterprise Networking
Campus and data center switches at 25G/50G per lane
Storage Controllers
NVMe/SAS HBAs and RAID controllers with multi-lane high-speed interfaces
Server Motherboards
DDR5 memory channels and PCIe Gen5 interconnect
Telecom Equipment
Router line cards and optical transport modules
High-Speed Digital
FPGA carrier boards and protocol analyzers
Medical Imaging
CT/MRI data acquisition boards with high channel counts
Design Guidance
Stackup Recommendations
- Use 1080 or 2116 glass styles for signal layers; combine with 7628 for power planes to optimize cost
- Maintain consistent Dk by using I-Tera MT40 prepreg throughout the signal layer stack
- Target 4.0–4.5 mil dielectric spacing for 100Ω differential impedance
Processing Tips
- Compatible with standard oxide or oxide-alternative inner-layer treatments
- Use RTF or VLP copper (Rz ≤ 5 µm) for best loss performance at 25G+
- No special drill parameters required — processes like standard high-Tg epoxy
Why AtlasPCB for I-Tera MT40?
Volume Pricing
Bulk material agreements with Isola ensure competitive per-panel pricing for production runs
Impedance Guarantee
±8% controlled impedance with coupon verification on every production lot
Fast Turnaround
In-stock material for standard thicknesses — prototypes ship in 5–7 working days
Frequently Asked Questions
Common questions about Isola I-Tera MT40 PCB fabrication
What is I-Tera MT40 best suited for?
I-Tera MT40 is optimized for 25G to 56G high-speed digital links including networking switches, storage controllers, and server backplanes where standard FR-4 introduces too much loss but ultra-low-loss materials are cost-prohibitive.
How does I-Tera MT40 compare to Isola 370HR?
I-Tera MT40 offers roughly 40% lower loss than 370HR (Df 0.0031 vs 0.005) while maintaining the same Tg of 200°C. It bridges the performance gap between standard high-Tg and ultra-low-loss materials.
What is the Dk and Df of I-Tera MT40?
I-Tera MT40 has a dielectric constant (Dk) of 3.45 ±0.05 and dissipation factor (Df) of 0.0031, both measured at 10 GHz using IPC-TM-650 methodology.
Is I-Tera MT40 compatible with lead-free assembly?
Yes. With a Tg of 200°C and Td of 360°C, I-Tera MT40 easily withstands multiple lead-free reflow cycles at 260°C peak temperature without delamination.
What layer counts does AtlasPCB support with I-Tera MT40?
AtlasPCB fabricates I-Tera MT40 boards from 4 to 32+ layers with controlled impedance, blind/buried vias, and sequential lamination for complex HDI designs.
Ready to Build with I-Tera MT40?
Upload your design files for a free DFM review and quote. Our team optimizes your stackup for the best balance of performance and cost.
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