Doosan DS-7409 Laminates: DV(N), DJN+, DJN2+, DQN and DYQ Compared

DS-7409 is not one laminate. It is the prefix Doosan uses for a family of high-speed copper-clad laminates, and the suffix decides the performance: on Doosan’s product pages, DS-7409DV(N) lists a Df of 0.0025 at 10 GHz, DS-7409DJN+ and DS-7409DQN list 0.0014, DS-7409DJN2+ lists 0.0011, and DS-7409DYQ lists 0.0006, all by the same IPC stripline method. That spread covers roughly the M6/M7 tier through M8 to the newest ultra-low-loss tier. This guide compares the published values of each grade, explains why Doosan lists two Df values for the same product, and shows how to specify the right one. For what the “M” tiers mean, see our M9 CCL guide.

What Is the Doosan DS-7409 Family?

A set of laminates and matching prepregs from Doosan’s electronic materials business, sold under one base name with letter suffixes. Each suffix is a separate product with its own resin, glass and datasheet; values do not carry over from one suffix to another, and there is no single “DS-7409” Df. Doosan’s own product pages and its combined properties document list them by suffix (product search, all-properties PDF, September 2024).

This matters on drawings and in RFQs. “DS-7409” alone does not tell a fabricator which product to buy, and a bare suffix that is close to another one (DQN versus DYQ, for example) can mean a several-fold difference in loss.

How Do the DS-7409 Grades Compare?

From each product’s current page (DV(N), DJN+, DQN, DJN2+, DYQ); typical values:

Two patterns stand out. DJN+ and DQN share the same published electrical values; the practical difference is that Doosan lists DQN as halogen-free. DJN2+ is a separate, lower-loss product, not a revision of DJN+: its 10 GHz Df is about 20% lower (0.0011) and its Dk drops to 2.69, with X/Y expansion of 10 ppm/°C; Doosan describes it as super-ultra-low loss for 800G routers, switches and base stations, and its page does not state halogen-free. DYQ is a different class again: less than half the 10 GHz Df of DJN+ and DQN, a much lower Dk (2.5), and an X/Y expansion of only 6 ppm/°C. The pages do not state resin content or sample thickness, so Dk for your stackup has to come from construction-specific data for the glass styles and resin contents you actually use.

Why Do Doosan Datasheets Show Two Df Values?

Because they use two test methods at 10 GHz. IPC-TM-650 2.5.5.5 is a stripline method; the split-post dielectric resonator (SPDR) measures the laminate in-plane. For the same product the SPDR result is higher: 0.0017 versus 0.0014 for DJN+ and DQN, 0.0015 versus 0.0011 for DJN2+, and 0.0037 versus 0.0025 for DV(N).

Neither number is wrong, but they are not interchangeable. When you compare DS-7409 against another maker’s laminate, compare like with like: a 2.5.5.5 value against a 2.5.5.5 value, or a resonator value against a resonator value. Mixing them can make one material look 20–50% better than it is. Better still, use the loss your channel actually sees, measured on coupons or modeled with construction-specific data.

Which DS-7409 Grade Fits Which Board?

Choose by loss budget, then check availability:

• DV(N): boards where standard high-speed FR-4 is too lossy but M8-class material is more than the channel needs, for example moderate-length links or less critical layers in a hybrid stack.
• DJN+: long high-speed channels in servers, switches and accelerators, where an M8-class Df is required.
• DQN: the same use as DJN+ when the program also requires halogen-free material.
• DJN2+: 800G switch, router and line-card channels that need more margin than DJN+ gives, before moving to the DYQ tier.
• DYQ: the longest or fastest channels where an M8-class material with smooth copper still does not close the loss budget.

Copper and glass matter as much as the suffix at these loss levels: smooth HVLP copper on the high-speed layers, and the glass style named per layer. The Blackwell material overview puts these tiers in the AI-server context; for matching materials to signal speed in HDI builds, our guide to matching HDI materials to signal speed.

How Does DS-7409DJN+ Compare with MEGTRON 8 and EM-892K2?

They sit in the same tier, but their datasheets use different methods and frequencies, so a direct ranking from Df alone is not reliable. EMC lists EM-892K2 at a 10 GHz Df of 0.0014 or 0.0013 by cavity resonator, depending on resin content (EM-892K2 datasheet, July 2024); Panasonic lists MEGTRON 8 at 14 GHz on a disk resonator. Our MEGTRON 8 guide and EM-892K2 guide give each material’s full data.

In practice the choice among them often comes down to construction-specific Dk tables, halogen-free requirements, the fabricator’s processing experience and lead time. If a design must allow substitutes, name them on the drawing and run the channel model with each one’s data. Tachyon 100G is another option in this tier.

Can You Mix DS-7409 Grades in One Stackup?

Yes, and it is a common way to control cost: the lowest-loss grade only on the fastest layers, a lower grade elsewhere. Three rules keep a hybrid build predictable:

• Use the prepreg that belongs to each core product unless the material maker confirms another combination.
• Check that the grades’ expansion and cure behavior are compatible; DYQ’s low in-plane expansion differs from the other grades.
• Have the fabricator propose the stackup with construction-specific Dk for each layer, and confirm impedance on coupons from the production panel.

Doosan offers technical support for CCL processing; the press cycle and desmear settings should come from its processing guide and the fabricator’s qualification, not from a generic FR-4 recipe.

What Should You Write on the Drawing?

How Can We Help?

QueenEMS builds high-layer-count multilayer and HDI boards on the laminate you specify. Send your stackup with the exact DS-7409 suffix and any approved alternatives; our bare-board quote, ready within 2 hours, tells you whether that grade is available and which construction we propose.

Conclusion

DS-7409 is a family, and the suffix decides what you get: DV(N) at a 10 GHz Df of 0.0025, DJN+ and DQN at 0.0014 (DQN halogen-free), DJN2+ at 0.0011, and DYQ at 0.0006 with a Dk of 2.5. Compare grades and competitors on the same test method, use matching prepregs in hybrid stacks, and write the full suffix, copper and glass on the drawing. Contact us and attach the stackup, the DS-7409 grade you want and your Gerber data.

FAQ

Is DS-7409 a single product? No. It is a family; each suffix (DV(N), DJN+, DQN, DJN2+, DYQ and others) is a separate laminate with its own datasheet.

What is the Df of DS-7409DJN+? 0.0014 at 10 GHz by IPC-TM-650 2.5.5.5, or 0.0017 by SPDR, on Doosan’s product page.

What is the difference between DS-7409DJN+ and DS-7409DQN? Their published electrical values are the same; Doosan lists DQN as halogen-free.

Is DS-7409DJN2+ the same as DJN+? No. DJN2+ is a separate lower-loss grade: Df 0.0011 and Dk 2.69 at 10 GHz, against 0.0014 and 2.9 for DJN+.

Is DS-7409DYQ an M9 material? Usually counted as one: its 10 GHz Df of 0.0006 is below the M8-class grades, but “M9” is an industry label, not a standard grade.

Can DS-7409DJN+ replace MEGTRON 8? Often, yes, in the same tier, but confirm with a channel model using each material’s construction-specific data and get the substitution approved.