Panasonic Megtron laminates
Megtron 6, Megtron 7 & Megtron 8: Low-Loss Laminates for 25–224G
Panasonic Megtron laminates for high-speed digital: Megtron 6 for 10–28G NRZ, Megtron 7 for 56–112G PAM4, and Megtron 8 for next-generation 112–224G AI and switch channels.
- Megtron 6 Df @ 13 GHz
- 0.0037
- Megtron 7 Df @ 14 GHz
- 0.0023
- Megtron 8
- Next-gen
- Compatible process
- FR-4
Overview
The Megtron family.
Megtron is Panasonic’s family of low-loss PCB laminates for high-speed digital design. Each generation (Megtron 6, 7 and 8) lowers the dissipation factor to support higher data rates and longer channels, and all of them process on standard multilayer lines with only minor parameter adjustments.
We fabricate multilayer and HDI boards on all three grades with controlled impedance, sequential lamination and back-drilling, for networking, storage, servers, AI accelerators and telecom.
Comparison
Megtron 6 vs 7 vs 8.
| Laminate | Series | Dk (typ.) | Df (typ.) | Typical data rate |
|---|---|---|---|---|
| Megtron 6 | R-5775(N) | 3.34 @ 13 GHz | 0.0037 @ 13 GHz | 10–28G NRZ; some 56G at short reach |
| Megtron 7 | R-5785(N) / R-578Y(N) | 3.31 @ 14 GHz | 0.0023 @ 14 GHz | 56G PAM4, 112G at shorter reach |
| Megtron 8 | R-5795N | See datasheet | Below Megtron 7 | 112–224G, AI fabrics |
| Standard FR-4 | — | ≈ 4.2 | ≈ 0.02 | Reference |
Megtron 6
Panasonic Megtron 6.
Megtron 6 (R-5775N series) is the entry point for high-speed designs. Panasonic’s April 2022 R-5775(N) data sheet lists typical Dk/Df of 3.40/0.002 at 1 GHz and 3.34/0.0037 at 13 GHz for its 0.750 mm core sample. The 1 GHz values use IPC-TM-650 2.5.5.9; the 13 GHz values use the balanced-type circular disk resonance method, IEC 63185. Select the construction-specific values for your model.
It is the workhorse for enterprise switches, storage controllers, server backplanes and telecom equipment running 10G/25G NRZ, and a clear step up from Isola 370HR or S1000-2M with no special drilling, plating or lamination steps.
Megtron 4
Megtron 4: the mid-loss step below Megtron 6.
Megtron 4 is Panasonic’s mid-loss grade, positioned between high-Tg FR-4 and Megtron 6. It suits 10G-class links and PCIe Gen 3/4 boards where standard FR-4 loses too much signal but Megtron 6 is more than the channel needs. It competes with Isola FR408HR and ITEQ IT-968; we compare them on loss, cost and lead time for your channel. Confirm exact Dk and Df values with the current Panasonic data sheet.
Megtron 7
Megtron 7.
Panasonic’s MEGTRON7 product data lists typical Dk 3.31 and Df 0.0023 at 14 GHz for the low-Dk-glass R-5785(N) / R-578Y(N) grades, using the balanced-type circular disk resonator method on a 0.75 mm sample. Other suffixes and constructions have different values. Evaluate the grade against the channel length, copper profile and loss budget.
At 56G PAM4, a few extra dB of insertion loss can push a channel below receiver sensitivity. For nominal 56 Gbps PAM4 the Nyquist frequency is 14 GHz; for 112 Gbps PAM4 it is 28 GHz, as illustrated in AMD XAPP1392. Compare materials at matching frequencies and test conditions; the exact interface rate may differ from its rounded marketing rate.
Megtron 8
Megtron 8.
Megtron 8 (R-5795N series) pushes loss lower again for 112 Gbps PAM4 and emerging 224 Gbps signaling: next-generation AI training clusters, 800G/1.6T switches and co-packaged optics. Lead times can be longer than for Megtron 6 and 7, so involve us early. See AI & data center PCB.
Selecting a grade
Selecting the right Megtron grade.
The right grade depends on data rate, trace length and loss budget. Megtron 6 gives enough margin at the lowest cost for 10G/25G NRZ with short to moderate traces. For 56G PAM4, Megtron 7 is the usual recommendation, and Megtron 6 is used only if simulation confirms margin. For 112G PAM4 and above, Megtron 8 or an equivalent ultra-low-loss laminate is the baseline.
Cost scales with performance. Megtron 8 costs roughly 2–3× as much per sheet as Megtron 6, with Megtron 7 in between. We can estimate insertion loss during stack-up planning so you choose the lowest-cost grade that meets the channel.
| Design | Suggested grade |
|---|---|
| PCIe Gen 4, 10/25GbE | Megtron 6 |
| PCIe Gen 5, 56G PAM4 | Megtron 6 (short) / Megtron 7 |
| 112G PAM4, PCIe Gen 6 | Megtron 7 / Megtron 8 |
| 224G | Megtron 8 or next-gen |
Fabrication
Fabrication considerations.
All three grades process on standard multilayer lines. Low-loss laminates are more sensitive to copper roughness than FR-4, though. Rough foil can add a meaningful fraction of a dB per inch at 28 GHz, so we specify HVLP or reverse-treated foil on signal layers so copper does not cancel the laminate’s advantage.
Controlled impedance to ±8% is standard, with tighter targets reviewed. Sequential lamination, back-drilling and via-in-pad are supported. Spread or flat glass styles help limit fiber-weave skew on long differential pairs.
- HVLP / RTF copper on signal layers
- Spread glass to reduce weave skew
- Back-drill via stubs on SerDes nets
- TDR coupons on every panel
Hybrid
Hybrid Megtron stack-ups.
Where only some layers carry high-speed signals, Megtron can be used for signal layers with lower-cost high-Tg FR-4 for power and ground planes. Tg, CTE and resin compatibility between the materials are checked before release, and impedance is modeled on the real mixed construction. Hybrids can cut material cost substantially on high-layer-count boards.
Megtron vs Rogers
Megtron vs Rogers.
Megtron is built for multilayer high-speed digital boards with many routing layers. Rogers laminates are built for RF and microwave, typically fewer layers with very tight Dk control. Data-center switches, servers and networking use Megtron. Antennas and RF front ends use Rogers. Telecom radios often combine both in one hybrid stack-up.
FAQ
Material questions.
What is the Df of Megtron 6?
For the R-5775(N) 0.750 mm sample in Panasonic’s April 2022 data sheet, typical Df is 0.002 at 1 GHz and 0.0037 at 13 GHz, using the specified test methods. These are typical values, not guaranteed values for every construction.
Megtron 6 vs Megtron 7?
Compare the exact grade and construction at the same frequency. The linked MEGTRON7 low-Dk-glass product data gives Df 0.0023 at 14 GHz; channel loss also depends on copper profile, routing geometry and length.
What data rates can Megtron support?
Megtron 6 to about 25–28G NRZ, Megtron 7 for 56G PAM4 and Megtron 8 for 112G and beyond.
Is Megtron 8 available?
Yes on request; lead time is confirmed at quote and can be longer than for Megtron 6/7.
Does Megtron need special processing?
No. It processes on standard multilayer lines with minor parameter adjustments.
Megtron or Rogers for my design?
Megtron for multilayer high-speed digital; Rogers for RF and microwave. Hybrid boards can use both.
Panasonic Megtron 6 vs Megtron 4?
Megtron 6 and Megtron 4 are different material systems. Compare grade-specific Dk/Df, test frequency, construction and channel requirements; the cited R-5775(N) data sheet gives Df 0.002 at 1 GHz and 0.0037 at 13 GHz.
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