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ITEQ IT-858T is a halogen-free metal base PCB laminate for LED lighting and power electronics thermal management. Full specs, fab tips, comparisons & FAQs.

When a design starts pushing past what standard FR-4 can handle thermally, the conversation usually shifts fast toward metal core PCB (MCPCB) materials. For engineers working on LED assemblies, consumer power electronics, and light-duty thermal management builds, the ITEQ IT-858T is a well-positioned entry in ITEQ’s IMS (Insulated Metal Substrate) product line — offering a practical thermal step-up without the cost premium of higher-conductivity specialist grades.

This guide covers what the ITEQ IT-858T is, where it sits in the IMS landscape, its technical characteristics, how to work with it during fabrication, and when it’s the right call versus when you should be looking at something else.

What Is ITEQ IT-858T? Placing It in the IMS Product Family

ITEQ Corporation, headquartered in Hsinchu, Taiwan, is one of the largest copper-clad laminate (CCL) manufacturers globally. Their IMS product line is smaller than their core FR-4 and high-speed digital portfolio, but covers the key thermal conductivity tiers that power electronics designers actually need.

The ITEQ IT-858T belongs to the IT-858 series — ITEQ’s metal base laminate family for thermally demanding single-sided and double-sided circuit board applications. Where the higher-spec IT-859GTA pushes thermal conductivity to 3.0 W/mK with glass fabric reinforcement, the IT-858T is positioned as the standard-performance IMS offering in ITEQ’s lineup: a filled-epoxy dielectric on an aluminum metal base, designed to serve the wide middle of the LED lighting and low-to-mid-power electronics market.

The naming convention is worth understanding briefly. In ITEQ’s IMS series:

• IT-858 family = standard thermal conductivity tier, aluminum metal base, filled epoxy dielectric
• IT-859 family = elevated thermal conductivity tier, glass fabric reinforced, for higher power density

The IT-858T targets applications where reliable thermal transfer, RoHS compliance, and lead-free assembly compatibility are required — but where the power density doesn’t yet demand the 3 W/mK performance of the IT-859 series.

ITEQ IT-858T Key Technical Specifications

The table below outlines the expected technical profile of the ITEQ IT-858T based on ITEQ’s published IMS product line data and IPC-TM-650 standard test methods referenced across their IMS family:

Property	Typical Value	Test Method
Glass Transition Temperature (Tg)	~105–115°C (DSC)	IPC-TM-650 2.4.25
Thermal Conductivity (Dielectric)	1.0–2.0 W/mK	—
Lead-Free Assembly Compatibility	Pass 260°C	IPC-TM-650 2.6.27
Halogen Content	Halogen-Free	IEC 61249-2-21
RoHS Compliance	Yes	EU RoHS Directive
Metal Base Material	Aluminum (standard)	—
UL Flame Rating	UL 94 V-0	UL 94
Dielectric Strength	≥3 kV/mm	IPC-TM-650 2.5.6
Available Copper Weights	1 oz to 3 oz (typical)	—
Board Thickness	1.0 mm to 2.0 mm	—

A note on published specifications: ITEQ’s IT-858T is not as extensively documented across third-party laminate databases as the IT-859GTA. When specifying this material, always request the current product datasheet directly from ITEQ or your approved PCB fabricator to confirm thermal conductivity tier and available panel sizes before committing to a design.

Understanding Thermal Conductivity in Metal Core PCB Design

Before evaluating whether the ITEQ IT-858T fits your application, it helps to understand exactly what the thermal conductivity specification does — and doesn’t — tell you.

In any MCPCB stack, the heat path from a component junction to the board’s metal base passes through several layers:

Junction → Solder Joint → Copper Trace → Dielectric Layer → Aluminum Base → Heatsink/Chassis

The dielectric layer is almost always the thermal bottleneck. Copper conducts at ~390 W/mK and aluminum at ~160–200 W/mK — both orders of magnitude above any polymer dielectric. So the dielectric’s thermal conductivity, combined with its thickness, sets the dominant thermal resistance in the stack.

The table below puts ITEQ’s IMS tiers in context:

Dielectric Thermal Conductivity	Typical Application Fit	Example ITEQ Grade
0.3 W/mK (standard FR-4)	Not suitable for IMS	—
1.0 W/mK (standard IMS)	Low-power LED, consumer electronics	IT-858T (standard tier)
1.5–2.0 W/mK (mid IMS)	Mid-power LED arrays, LED drivers	IT-858T (upgraded tier)
3.0 W/mK (high IMS)	High-power LED, automotive lighting	IT-859GTA
4.0+ W/mK (premium IMS)	Extreme power density	Premium specialist grades

For a 3W–5W LED module at moderate ambient temperatures, a 1.0–1.5 W/mK IMS dielectric is typically adequate. Once you move into 8W+ per LED cluster, per-device power densities above 20 W/cm², or operating ambients above 55°C, the conversation shifts toward the 3 W/mK tier.

Target Applications for ITEQ IT-858T

The ITEQ IT-858T is designed for thermally aware applications where standard FR-4 creates reliability risks but the highest-performance IMS grades are overspecified. In practice, this covers a broad and commercially important segment:

LED Lighting Applications

• Residential and commercial LED downlights
• LED retrofit lamp boards (A-lamp, GU10, MR16 formats)
• LED strip board substrates (low-to-mid power)
• Indoor LED panel light bases
• LED driver boards with onboard power components
• Decorative and architectural lighting modules

Power Electronics Applications

• Switching power supply (SMPS) base boards up to ~50W
• Low-voltage DC-DC converter assemblies
• Battery management circuit boards
• Solid-state relay substrates
• Small motor drive stages
• Power adapter and charger boards

The common thread across all these applications is a design that dissipates meaningful heat — enough to damage FR-4 or create reliability problems over time — but doesn’t need the extreme thermal transfer of high-power outdoor LED or industrial motor drive builds.

ITEQ IT-858T vs. Competing IMS Materials: Practical Comparison

If you’re shortlisting IMS materials in this thermal performance tier, here’s how the ITEQ IT-858T compares to the alternatives engineers commonly evaluate:

Material	Manufacturer	Thermal Conductivity	Halogen-Free	Notes
IT-858T	ITEQ	1.0–2.0 W/mK	Yes	Standard IMS tier, broad applicability
IT-859GTA	ITEQ	3.0 W/mK	Yes	Glass fabric reinforced, higher power density
VT-4A1	Ventec	1.6 W/mK	Yes	Well-known alternative, similar tier
HL-01	Bergquist/Henkel	1.0 W/mK	Varies	Common in North American supply chains
S1141	Shengyi	~1.0 W/mK	Varies	Low-cost alternative, common in Asia
VT-4B3	Ventec	3.0 W/mK	Yes	Step up to high thermal tier

For most LED and low-power electronics designs, the IT-858T and its tier equivalents (Ventec VT-4A1, Bergquist GP1000-series) are functionally interchangeable at the specification level, though supply chain, UL documentation, and fabricator qualification may influence the actual choice in production.

When to step up to IT-859GTA: If your thermal simulation shows junction temperatures above 85°C at rated load, or if total board power density exceeds ~20 W/cm², the 3 W/mK grade is worth the cost difference. The dielectric thermal resistance at 3 W/mK is roughly half that of a 1.5 W/mK dielectric at the same thickness — a meaningful margin that compounds over LED lifespan and thermal cycling count.

How ITEQ IT-858T Fits Into the ITEQ IMS Product Line

ITEQ’s IMS (Insulated Metal Substrate) product line is relatively focused compared to their sprawling FR-4 and high-speed digital catalog. Based on ITEQ’s published IMS product information, their metal base range includes:

Grade	Thermal Conductivity	Key Feature	Typical Application
IT-858T	1.0–2.0 W/mK	Standard IMS, halogen-free epoxy	LED lighting, consumer power electronics
IT-859GTA	3.0 W/mK	Glass fabric reinforced, high thermal	High-power LED, automotive lighting, street lamps

This two-tier structure — standard thermal and high thermal — covers the majority of what the LED and power electronics market actually needs from an IMS material. Engineers working on low-to-mid power applications should start with the IT-858T on cost grounds; those running higher power budgets should evaluate the IT-859GTA directly.

For a deeper look at the full ITEQ PCB product range — including current IMS availability, stack-up support, and prototype pricing — ³Ô¹Ïtv is a strong starting resource for sourcing and technical guidance.

Fabrication Notes for ITEQ IT-858T Boards

Working with any aluminum-base IMS laminate introduces fabrication considerations that don’t apply to standard FR-4. If you’re specifying IT-858T boards for the first time, these are the practical points worth discussing with your fabrication house before taping out:

Drilling and Routing

Aluminum MCPCB requires carbide tooling and controlled feed rates. Standard PCB drill bits dull quickly against the metal base. Make sure your fab confirms their tooling is qualified for IMS. Route contours — especially internal cutouts — need to be planned early, as the aluminum base cannot be scored and snapped the way FR-4 can.

Depaneling

This is the area where most first-time IMS designs encounter problems. Discuss depaneling method before finalizing the panel layout. V-scoring works on aluminum IMS, but requires scoring blades rated for the metal. Routing is possible but adds cost. Tab routing with breakaway tabs is viable for prototype quantities. Whatever method you choose, account for it in your panel tolerance stack-up.

Solder Mask Selection

For LED assemblies, white solder mask is almost always the right choice. White solder mask on an aluminum MCPCB typically achieves over 85% light reflectance, recovering photons that would otherwise be lost to absorption. For pure power electronics builds where optical performance isn’t a factor, standard green solder mask is fine.

Surface Finish

ENIG (Electroless Nickel Immersion Gold) is the preferred surface finish for IT-858T boards used in LED applications. ENIG gives a flatter, more consistent pad surface for fine-pitch LED packages and is well-matched to lead-free soldering profiles. For larger components or cost-sensitive designs, lead-free HASL is workable.

Hi-Pot Testing

Because aluminum MCPCB is inherently a board with a live conductor adjacent to a metal substrate, dielectric withstand voltage (hi-pot) testing is standard practice for IMS builds going into power or lighting end products. Specify a minimum 1,500V AC hi-pot test in your fabrication notes. For line-voltage products (AC mains), 3,000V AC is more appropriate.

Storage and Handling

Store IT-858T panels sealed with desiccant in a cool, dry environment. Aluminum surfaces oxidize in humid conditions, which can affect adhesion during lamination and solder wettability at the board edge. Follow the recommended bake-out procedure if material has been in ambient storage for more than a few weeks before lamination.

Useful Resources for Engineers

Resource	Description	Link
ITEQ IMS Product Page	Official ITEQ IMS product listing including IT-858T and IT-859GTA
ITEQ Corporation UL Recognition (E178114)	UL Prospector listing for ITEQ IMS laminate certifications
PCB Directory – ITEQ Laminates	Third-party laminate database with ITEQ product datasheet downloads
IPC-TM-650 Test Methods	Standard test methods referenced in all IMS laminate datasheets
Ventec VT-4A1 Datasheet	Useful benchmark for cross-referencing 1.6 W/mK IMS specifications
PCBSync ITEQ Materials Overview	Practical engineer-focused overview of ITEQ laminate selection

5 FAQs About ITEQ IT-858T

1. What is the thermal conductivity of ITEQ IT-858T and is it sufficient for LED designs?

The IT-858T sits in the 1.0–2.0 W/mK thermal conductivity range — the standard IMS tier. For most LED applications up to approximately 5W per device, this is adequate, particularly when combined with good thermal interface material at the board-to-heatsink interface and appropriate copper weight for current spreading. If your design is running higher power densities — say, 8W+ per LED cluster or total board dissipation above 50W in a compact footprint — the IT-859GTA at 3.0 W/mK is worth the additional cost. Always run a thermal simulation or at least a hand calculation of junction-to-ambient thermal resistance before locking in your IMS grade.

2. Is ITEQ IT-858T halogen-free and RoHS compliant?

Yes. The IT-858T uses a halogen-free filled epoxy dielectric formulation, meeting IEC 61249-2-21 limits (Cl + Br < 1500 ppm combined). It is fully RoHS compliant, making it appropriate for products sold into the EU, UK, China (China RoHS), and other major markets with environmental material restrictions. The 260°C lead-free assembly compatibility ensures it survives modern no-clean and SAC305 soldering profiles without delamination concerns.

3. Can ITEQ IT-858T be used for double-sided assemblies?

Yes, though single-sided construction is far more common for MCPCB designs. The aluminum substrate in a standard IMS build terminates vias — you cannot route signals through the metal base to a second copper layer without specialized construction. True double-sided IMS is available but requires a dielectric separation layer within the stack, which adds cost and typically reduces thermal performance relative to a true single-sided MCPCB. For most LED and power electronics applications, single-sided construction covers the requirements. If you genuinely need two copper layers with full component access on both sides, consider whether a hybrid IMS-FR-4 construction or a thick copper FR-4 board might better serve the design.

4. How does ITEQ IT-858T compare to the IT-859GTA?

The IT-858T is the standard thermal performance IMS grade; the IT-859GTA is the high thermal performance grade with glass fabric reinforcement and 3.0 W/mK conductivity. The practical difference is roughly 2x the dielectric thermal conductivity — which translates to approximately 2x lower junction-to-substrate thermal resistance at the same dielectric thickness. For cost-driven designs with moderate power density, IT-858T is the sensible starting point. For designs where LED lifespan, operating temperature headroom, or high ambient temperature conditions drive the thermal budget, IT-859GTA is the correct choice. Avoid treating the upgrade as optional if your thermal simulation shows junction temperatures above 80–85°C at rated power.

5. What copper weights are available for ITEQ IT-858T and how should I choose?

The IT-858T is typically available in 1 oz (35 µm) and 2 oz (70 µm) copper, with some fabricators offering 3 oz. For LED applications, 1 oz copper is standard — sufficient for the current levels in typical LED arrays and fine for SMT LED package pads. For power electronics applications where you’re carrying significant continuous current (5A+), 2 oz copper reduces resistive heating in traces and improves current-spreading across the board surface. The copper layer’s role in lateral heat spreading is underappreciated: heavier copper conducts heat laterally across the board surface before it passes through the dielectric, effectively increasing the thermal spreading area and reducing peak dielectric flux. For high-current power boards, specify 2 oz minimum.

Engineer’s Summary

The ITEQ IT-858T fills a practical, commercially important slot in the IMS laminate market: a halogen-free, lead-free compatible, aluminum metal base laminate for LED lighting and power electronics designs that have outgrown FR-4 thermally but don’t yet need the elevated performance of a 3 W/mK grade.

It’s not the most documented material in ITEQ’s catalog — the IT-859GTA gets more coverage because it occupies a more distinctive performance position. But for the large volume of LED boards and small power electronics assemblies running in the 5W–30W range, the IT-858T represents an appropriate, cost-effective, and supply-chain-manageable choice when specified correctly and paired with the right fabrication parameters.

When you’re building LED boards and the FR-4 thermal argument no longer holds up, IT-858T is a solid first IMS call.