Tachyon 100G is an ultra-low-loss laminate and prepreg made by Isola, used for high-speed digital boards such as 100G-and-faster Ethernet line cards, backplanes and server boards. On Isola’s datasheet (Revision H, 2026) it has a Tg of 215°C (DSC), a Td of 360°C, and a Dk of 3.02 and Df of 0.0021 at 10 GHz, with spread glass and very-low-profile copper options. This page puts the official numbers in one place, explains why the Dk and Df you design with depend on the glass style and resin content, and lists what to specify when you order. For other laminates, see our PCB materials guide.
1. What Is Tachyon 100G?
An Isola laminate system for high-speed digital designs where standard and mid-loss materials lose too much signal. It is listed under IPC-4101 slash sheet /102 for the laminate and IPC-4103 /17 for the prepreg (IPC-4103 contents), and Isola describes it as:
- Lead-free compatible: rated for 6 reflow cycles at 260°C and 6 solder floats at 288°C.
- Suitable for multiple lamination cycles and HDI builds.
- CAF resistant and RoHS compliant, UL 94 V-0 (UL file E41625).
- Built with low-Dk, square-weave, mechanically spread glass, which reduces skew in differential pairs.
- Available with very-low-profile copper: HVLP3 (≤1.1 µm Rz), HVLP (≤2.5 µm) and advanced RTF (≤2.5 µm).
Source: Isola Tachyon 100G datasheet, Revision H.
2. What Does the Datasheet Say?
Typical values from Isola’s datasheet, with the test method Isola lists:
| Property | Tachyon 100G | Method |
|---|---|---|
| Tg | 215°C (DSC), 230°C (DMA), 210°C (TMA) | IPC-TM-650 2.4.25 / 2.4.24.4 / 2.4.24 |
| Td (5% weight loss) | 360°C | IPC-TM-650 2.4.24.6 |
| Time to delaminate | T260 > 60 min, T288 > 60 min, T300 > 20 min | IPC-TM-650 2.4.24.1 |
| Z-axis CTE below / above Tg | 45 / 250 ppm/°C | IPC-TM-650 2.4.24 |
| Z-axis expansion, 50–260°C | 2.5% | IPC-TM-650 2.4.24 |
| X/Y CTE below Tg | 15 ppm/°C | IPC-TM-650 2.4.24 |
| Dk at 2 / 5 / 10 GHz | 3.04 / 3.02 / 3.02 | IPC-TM-650 2.5.5.5 |
| Df at 2, 5 and 10 GHz | 0.0021 | Bereskin stripline |
| Thermal conductivity | 0.42 W/m·K | ASTM E1952 |
| Moisture absorption | 0.1% | IPC-TM-650 2.6.2.1 |
| Peel strength (low-profile copper) | 0.79 N/mm (4.5 lb/in) | IPC-TM-650 2.4.8 |
| CTI | Class 3 (175–249 V) | UL 746A |
| Flammability | V-0 | UL 94 |
Isola states the electrical properties hold from −55°C to +125°C and up to 100 GHz. For comparison, a common high-Tg FR-4 such as Isola 370HR lists a Df of 0.025 at 10 GHz, about 12 times higher; see our FR-4 material guide.
3. Why Do Dk and Df Change With the Glass Style?
Because each core and prepreg is a different mix of glass and resin, and the resin has a lower Dk than the glass. Isola publishes values for each construction; at 10 GHz:
| Construction | Resin content | Thickness | Dk | Df |
|---|---|---|---|---|
| Core 1×3313 | 58.5% | 0.102 mm (4 mil) | 3.24 | 0.0022 |
| Core 1×1078 | 70.5% | 0.089 mm (3.5 mil) | 3.02 | 0.0016 |
| Core 2×1067 | 72.5% | 0.127 mm (5 mil) | 2.98 | 0.0015 |
| Prepreg 2116 | 62.0% | 0.147 mm | 3.19 | 0.0021 |
| Prepreg 1078 | 75.0% | 0.107 mm | 2.97 | 0.0014 |
| Prepreg 106 | 76.0% | 0.058 mm | 2.95 | 0.0014 |
Source: Isola Tachyon 100G Dk/Df tables (the tables do not state the test method).
Two practical consequences:
- Impedance: a stackup calculated with one Dk (say 3.02) will be off if the fabricator builds it with a glass style that gives 3.24. Agree the constructions per layer, or let the fabricator propose them and calculate impedance from those.
- Loss: resin-rich constructions have lower Df. When you compare Tachyon 100G with another laminate, compare the same frequency, resin content and test method.
If the same board also carries RF transmission lines, include their operating frequency, loss and impedance requirements in an RF PCB manufacturing review. The exact laminate and stack-up still need confirmation for that design.
4. Why Do Copper Profile and Spread Glass Matter?
At the frequencies these boards run, current flows in a thin layer at the copper surface, so rough copper adds loss. Choosing HVLP or HVLP3 copper lowers conductor loss on top of the laminate’s low Df. Spread glass fills the gaps between glass bundles more evenly, so the two traces of a differential pair see a more uniform Dk, which reduces skew. Both are ordering choices: write the copper type and glass styles on the drawing, or they may be substituted.
5. When Is Tachyon 100G the Right Choice?
When channel loss, not heat, is the limit: long traces at high data rates, backplanes, switch and server line cards, and high-layer-count boards that also need multiple lamination cycles or HDI. Compare it with alternatives on the same basis (frequency, construction and method), and confirm availability and lead time with your fabricator before you commit. IEEE 802.3 task force presentations, such as this 100GEL contribution, show how laminate loss is budgeted in high-speed channels.
For hybrid builds, ultra-low-loss cores are often used only on the high-speed layers, with lower-cost material elsewhere; the materials must be compatible in lamination and expansion, so agree the build with the fabricator. For AI server context, see our NVIDIA Blackwell PCB material guide.
6. How Do You Specify Tachyon 100G on a PCB Order?
| Item | What to write |
|---|---|
| Material | Isola Tachyon 100G laminate and prepreg |
| Specification | IPC-4101 /102 (laminate), IPC-4103 /17 (prepreg) |
| Copper | Foil type per layer (e.g. HVLP3) and weight |
| Constructions | Glass style and resin content per layer, or “fabricator to propose for approval” |
| Impedance | Targets, tolerance and test method (coupon or TDR) |
| Substitutes | “No substitution without written approval,” or a list of approved alternatives |
| Via structure | Through, blind/buried or HDI, and back-drill requirements |
A DFM review before the PO catches construction and impedance mismatches early. For backplanes, see our high-speed backplane PCB RFQ guide.
How Can We Help?
Send your stackup with the laminate and copper you specified, and we will confirm material availability, constructions and impedance in the quote; bare-board quotes come back within 2 hours. We build multilayer boards up to 40 layers as well as HDI PCBs, and you can compare candidate laminates with our PCB material selector.
Conclusion
Tachyon 100G is Isola’s ultra-low-loss laminate for high-speed digital boards: Tg 215°C, Td 360°C, T288 over 60 minutes, and Dk 3.02 / Df 0.0021 at 10 GHz on the main datasheet, with spread glass and very-low-profile copper. The Dk and Df you design with depend on the glass style and resin content of each layer, so agree the constructions, copper and substitution rules on the drawing. Contact us with your stackup for a quote.
FAQ
Who makes Tachyon 100G? Isola Group.
What are the electrical properties of Tachyon 100G? On Isola’s datasheet: Dk 3.02 and Df 0.0021 at 10 GHz (Bereskin stripline for Df), with construction-specific values from about 2.92 to 3.25 Dk and 0.0013 to 0.0022 Df depending on glass style and resin content.
What is the Tg of Tachyon 100G? 215°C by DSC, 230°C by DMA and 210°C by TMA.
Is Tachyon 100G compatible with lead-free assembly? Yes. Isola rates it for 6 reflow cycles at 260°C, with a Td of 360°C and T288 over 60 minutes.
What is a PCB laminate? The copper-clad core material a board is built from, with prepreg sheets bonding the layers; Tachyon 100G is supplied as both.
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