What Is EM-890K? Datasheet Values and EMC Comparisons

You see EM-890K on a stackup drawing or a laminate substitution request and need to know what it is, what its datasheet actually says, and what it can be swapped with. EM-890K (with its prepreg, EM-89BK) is a halogen-free, low-loss laminate from Elite Material Co. (EMC) in Taiwan, used for high-speed digital boards such as servers and network switches. On EMC’s July 2024 datasheet it has a TMA Tg of 170°C, a Td of 430°C, and Dk 3.0 / Df 0.0025 at 10 GHz (cavity method, 55% resin content). This page puts the official numbers in one place, compares EM-890K with its EMC siblings, and lists what to write on your drawing. For other laminates, see our full PCB materials guide.

1. What Is EM-890K?

It is EMC’s halogen-free low-loss core material; EM-89BK is the matching prepreg. “Halogen-free” means it does not rely on brominated flame retardants, which matters for customers with halogen-free requirements. It is listed under IPC-4101 slash sheet /134 for the laminate, and IPC-4103 /230 and /530 (EMC EM-890K datasheet, Rev. July 2024).

• Use: high-speed digital layers where standard FR-4 loss is too high.
• Form: core (EM-890K) and prepreg (EM-89BK), usually combined in a stackup with the same system.
• What it is not: a guarantee of a specific data rate or trace length. Channel loss depends on the whole stackup, copper roughness and design.

2. What Does the Datasheet Say?

These are typical values from EMC’s July 2024 datasheet, with the test method EMC states. Typical values describe the stated test construction, not a guaranteed specification for every board.

Why do two Df values appear at 10 GHz?

Because two different test methods give different results. The cavity method gives 0.0025, and the split-post cavity (SPC) method gives 0.0019 for the same 55% resin content. When you compare EM-890K with another laminate, compare values from the same method, frequency and resin content. Mixing them makes a laminate look better or worse than it is.

3. How Does It Compare with Other EMC Laminates?

EM-890K sits in the middle of EMC’s low-loss range: lower loss than EM-890 and EM-528K, higher loss than EM-892K and EM-892K2. All values below are from EMC’s July 2024 datasheets, cavity method at 10 GHz, 55% resin content (EM-528K at 50%).

Sources: EMC datasheets for EM-890, EM-891K, EM-892K, EM-892K2 and EM-528K. A dash means the value was not given in the summary we used.

Two points from the table are easy to miss:

• EM-891K is not halogen-free, even though its name sits between EM-890K and EM-892K. If your project requires halogen-free material, do not accept it as a substitute.
• The “K” does not have one fixed meaning. EM-890 and EM-890K share the same Tg but have different Dk and Df, and EMC’s datasheets do not define “K” as a universal rule.

For the next step down in loss, see our article on the EM-892K2 halogen-free laminate.

4. Are There Other Halogen-Free Low-Loss Laminates?

Yes. Other laminate makers publish halogen-free materials in a similar loss range. Two examples from the makers’ own data:

These numbers come from different test setups and resin contents, so they screen candidates; they do not prove two laminates are interchangeable. A substitute needs the same slash sheet (or an approved alternative), a stackup recalculation for impedance, and, for high-speed channels, a loss check.

Can you move from EM-892K2 to EM-890K to save cost?

Sometimes, but there is no fixed saving. EM-890K has higher loss than EM-892K2 (0.0025 vs 0.0014 cavity Df at 10 GHz), so the swap only works where your loss budget allows it. Cost depends on the construction, copper, quantity and quote date; compare real quotes for the same stackup. Lead time can also differ between laminates; see our M8 laminate lead time comparison, or our guide to Tachyon 100G for a non-EMC option.

5. How Do You Specify It on a PCB Drawing?

Name the material, the slash sheet and what substitutes you will accept. Writing “EM-890K or equivalent” without defining “equivalent” lets a fabricator pick any material it considers close.

Can it be mixed with FR-4 in one stackup?

It can, with the fabricator’s approval. Hybrid stackups put low-loss cores on the high-speed layers and lower-cost material elsewhere, but the two materials must be compatible in lamination and CTE. Our halogen-free PCB manufacturing rules cover what to agree before mixing materials, and our HDI PCB page covers sequential lamination builds.

How can we help?

Send your stackup, the laminate you specified and any approved alternatives with your Gerber files, and we will confirm material availability and the stackup in the quote. You can also compare candidates with our PCB material selector. We quote within 24 hours with no minimum order quantity.

Conclusion

EM-890K is EMC’s halogen-free, low-loss core, with a TMA Tg of 170°C, Td of 430°C and cavity Df of 0.0025 at 10 GHz on its July 2024 datasheet. It sits between EM-890 and EM-892K in EMC’s range, EM-891K is not a halogen-free substitute, and other makers offer halogen-free materials in a similar loss range. Compare laminates using the same test method and resin content, and write the slash sheet and substitution rules on your drawing. Send your stackup and contact us today for a quote.

FAQ

What is EM-890K? A halogen-free, low-loss PCB laminate core made by Elite Material Co. (EMC), used with EM-89BK prepreg for high-speed digital boards.

What is the Tg of EM-890K? 170°C by TMA and 205°C by DMA, according to EMC’s July 2024 datasheet.

What is the Df of EM-890K? 0.0025 at 10 GHz by cavity resonator at 55% resin content; the split-post cavity method gives 0.0019 under the same conditions.

What is the difference between EM-890K and EM-892K? EM-892K has lower loss (cavity Df 0.0019 vs 0.0025 at 10 GHz), a higher Tg (180°C vs 170°C TMA) and lower Z-axis expansion (1.8% vs 2.2%). Both are halogen-free.

What IPC slash sheet is EM-890K? IPC-4101 /134 for the laminate.