What Is Bergquist PCB? Materials, Applications & Thermal Performance Explained

If you’ve ever had an LED driver board fail in the field, or watched junction temperatures climb on a power module prototype, you already know why thermal management matters. Standard FR4 just doesn’t cut it for high-watt-density applications. That’s where Bergquist PCB materials come into play.

I’ve been specifying Bergquist Thermal Clad substrates for over a decade now, primarily in LED lighting and power conversion designs. This guide covers everything you need to know about selecting the right Bergquist material for your application—from part numbers and specifications to real-world thermal performance comparisons.

Understanding Bergquist PCB Technology

Bergquist PCB refers to a family of insulated metal substrate (IMS) materials originally developed by The Bergquist Company in the late 1980s. The technology was among the first commercially available metal core PCB solutions designed specifically for high-power surface mount applications where conventional FR4 boards simply couldn’t handle the thermal load.

The company changed hands over the years. Henkel acquired Bergquist in 2014, bringing global manufacturing resources and expanded distribution. Then in 2021, Polytronics Technology Corporation purchased the Thermal Clad division from Henkel and formed TCLAD Inc., which now operates from the original 100,000 square foot facility in Prescott, Wisconsin with over 200 employees dedicated to thermal management solutions.

Despite the ownership changes, the core technology remains the same: a thermally conductive dielectric layer bonded between a metal base (typically aluminum or copper) and a copper circuit layer. This three-layer construction creates an efficient thermal path from surface-mounted components directly to a heat sink or chassis.

How Thermal Clad Works

The secret to Bergquist’s performance lies in its proprietary dielectric layer. Unlike standard FR4 prepreg, Thermal Clad uses a polymer-ceramic blend specifically engineered for:

• High thermal conductivity (1.0 to 4.1 W/m-K depending on grade)
• Excellent electrical isolation
• Strong mechanical bonding between layers
• Resistance to thermal aging

This dielectric can maintain its properties at thicknesses as thin as 38 µm (0.0015 inches) for high-power LED applications, which is critical for minimizing thermal resistance.

Bergquist Material Part Numbers and Specifications

Choosing the right Bergquist material starts with understanding the part numbering system. The designation typically indicates the series (HT, MP, HPL, LTI, CML) followed by thickness codes.

Primary Material Families

HT Series (High Temperature) – Designed for applications requiring elevated operating temperatures up to 150°C. Features 2.2 W/m-K thermal conductivity with excellent resistance to thermal degradation.

MP Series (Multi-Purpose) – The workhorse of the lineup. Offers 1.3 W/m-K conductivity at a lower cost point, suitable for general LED and power conversion applications.

HPL Series (High Power Lighting) – Purpose-built for demanding LED applications with the thinnest dielectric (38 µm) and 3.0 W/m-K conductivity.

LTI Series (Low Thermal Impedance) – Optimized for low thermal resistance with 2.2 W/m-K conductivity, available in multiple thicknesses.

CML Series – Lower conductivity (1.1 W/m-K) but higher peel strength, used where mechanical robustness is prioritized.

Complete Specifications Table

Part Number	Dielectric Thickness (mil/µm)	Thermal Impedance (°C·in²/W)	Thermal Conductivity (W/m-K)	Breakdown Voltage (kVAC)	Glass Transition Tg (°C)	UL Index (°C)
HT-04503	3 / 76	0.05	2.2	6.0	150	140
HT-07006	6 / 152	0.11	2.2	11.0	150	140
HT-09009	9 / 229	0.16	2.2	20.0	150	150
MP-06503	3 / 76	0.09	1.3	8.5	90	130
LTI-04503	3 / 75	0.05	2.2	6.5	90	130
LTI-05004	4 / 100	0.05	2.2	7.5	90	130
LTI-06005	5 / 125	0.06	2.2	9.5	90	130
LTI-07006	6 / 150	0.07	2.2	11.0	90	130
HPL-03015	1.5 / 38	0.02	3.0	2.5	185	**
CML-11006	6 / 152	0.21	1.1	10.0	90	130

Note: HPL-03015 has limited UL recognition due to its thin dielectric—check with your safety engineer for specific requirements.

Selecting by Application

Here’s how I typically approach material selection:

For high-brightness LED arrays (>3W per LED): Start with HPL-03015. The 0.02 °C·in²/W thermal impedance makes a measurable difference in junction temperature.

For general LED lighting (1-3W LEDs): MP-06503 offers the best cost-performance balance. Most commercial LED fixtures use this grade.

For power conversion and motor drives: HT-04503 or HT-07006 depending on voltage requirements. The 6-mil variant gives you 11 kVAC breakdown for higher voltage applications.

For automotive or harsh environments: HT series with its 150°C Tg handles temperature cycling better than MP or LTI grades.

Bergquist PCB vs FR4: Thermal Performance Comparison

The thermal performance gap between Bergquist Thermal Clad and standard FR4 is substantial. Here’s what the numbers actually look like in practice.

Thermal Conductivity Comparison

Material Type	Thermal Conductivity (W/m-K)	Relative Performance
Standard FR4	0.2 – 0.3	Baseline
Bergquist MP Series	1.3	4-6x better
Bergquist HT/LTI Series	2.2	7-11x better
Bergquist HPL Series	3.0	10-15x better
Aluminum Substrate	205	–
Copper Substrate	390	–

The dielectric layer is the thermal bottleneck in any metal core PCB. That’s why Bergquist’s 2.2 W/m-K HT material makes such a difference compared to standard epoxy-glass prepreg at 0.3 W/m-K.

Real-World Impact

I ran thermal simulations on a 10W LED module comparing FR4 with thermal vias against Bergquist HT-04503. The results:

• FR4 with thermal vias: LED junction temperature 78°C above ambient
• Bergquist HT-04503: LED junction temperature 42°C above ambient

That 36°C difference translates directly to LED lifetime. Most LED manufacturers specify a 50% reduction in rated life for every 10°C increase in junction temperature.

When FR4 Makes Sense

To be fair, FR4 isn’t always the wrong choice. For applications under 1W/cm² power density with adequate airflow, FR4 with proper thermal via design can work. The cost difference is significant—Bergquist materials typically run 5-10x the price of standard FR4.

The break-even calculation depends on:

• Heat sink cost reduction (Bergquist often eliminates separate heat sinks)
• Assembly simplification (fewer thermal interface materials needed)
• Reliability requirements (lower operating temperature = longer life)
• Warranty cost exposure

Key Applications for Bergquist PCB

LED Lighting Systems

This remains the largest application segment. High-brightness LEDs generate significant heat in a small area, and proper thermal management directly impacts:

• Light output (LEDs dim as junction temperature rises)
• Color consistency (wavelength shifts with temperature)
• Operating life (exponential degradation with temperature)

Bergquist materials are used across residential, commercial, automotive, and architectural lighting. The HPL-03015 grade was specifically developed for this market, offering the thinnest available dielectric (38 µm) for maximum thermal performance.

In my experience designing LED modules, switching from FR4 with thermal vias to Bergquist HPL typically drops junction temperature by 25-40°C. That’s the difference between a 50,000-hour rated life and premature failure within 10,000 hours.

Typical LED applications include:

• Street lighting modules requiring UL/CSA certification
• Automotive headlight and taillight assemblies
• Commercial high-bay and low-bay fixtures
• Architectural accent and cove lighting
• Medical examination lamps requiring consistent color temperature

Power Electronics and Conversion

Power modules, DC-DC converters, and motor drives benefit from Thermal Clad’s ability to spread heat from localized sources. The aluminum or copper base acts as a heat spreader, reducing thermal gradients across the board and allowing more uniform heat transfer to external heat sinks.

Common power electronics applications:

• IGBT and MOSFET mounting for inverters
• Solid-state relay modules
• Power factor correction circuits
• Switch-mode power supply modules
• Battery management systems for EVs
• Solar microinverters

The HT series is particularly popular here due to its high-temperature stability and voltage breakdown characteristics. For applications exceeding 500V working voltage, the HT-07006 (6-mil dielectric) provides 11 kVAC breakdown with comfortable margin.

One underappreciated benefit in power applications: the metal base provides excellent EMI shielding. Ground plane connection to the aluminum substrate creates an effective shield against radiated emissions from switching circuits.

Automotive Electronics

Electric vehicles have driven significant growth in high-performance thermal substrates. The automotive sector’s stringent reliability requirements—AEC-Q100 qualification, extensive temperature cycling, vibration testing—match well with Bergquist’s established performance data.

Key automotive applications:

• Traction inverter modules (IGBT/SiC mounting)
• On-board charger power stages
• DC-DC converter modules
• Battery thermal management circuits
• LED headlamp and DRL modules
• Instrument cluster backlighting
• ADAS sensor power supplies

Automotive qualification requires materials that handle temperature cycling from -40°C to +150°C—the HT series with its 150°C glass transition temperature meets these requirements. Many manufacturers require 1000+ temperature cycles with no degradation in thermal or electrical performance.

The automotive sector also appreciates Bergquist’s consistent supply chain and lot traceability. When you’re designing for a 7-year production run with potential warranty exposure, material consistency matters.

Industrial and Aerospace

Motor controllers, solar inverters, and aerospace power systems use Bergquist materials where reliability is non-negotiable. The military and aerospace sectors particularly value:

• Long-term thermal stability (25+ year service life requirements)
• Consistent lot-to-lot performance for production continuity
• Full material traceability for failure analysis
• Established qualification data from decades of field experience
• Known radiation tolerance for space applications

Industrial applications span welding power supplies, CNC machine servo drives, solar string inverters, and wind turbine converters. The common thread is high power density with continuous operation in demanding environments.

Telecommunications and Data Centers

5G infrastructure rollout has created demand for high-power RF amplifiers and power supplies that can operate reliably in outdoor cabinets. Data center power distribution uses Thermal Clad for high-density rectifier and inverter modules where cooling capacity is always constrained.

The telecom industry particularly values Bergquist Gap Pad products (separate from Thermal Clad) for thermal interface between components and heat sinks. These gap-filling materials complement the PCB substrate for complete thermal management solutions.

Bergquist Thermal Interface Materials

Beyond Thermal Clad PCB substrates, Bergquist (now under Henkel’s ownership for TIM products) offers a complete portfolio of thermal interface materials that complement metal core PCBs. Understanding these products helps create complete thermal management solutions.

Gap Pads and Gap Fillers

Gap Pads are soft, conformable pads that fill air gaps between heat-generating components and heat sinks. Key product lines include:

Product	Thermal Conductivity	Key Feature
Gap Pad VO	0.8-1.0 W/m-K	Silicone-free, telecom applications
Gap Pad 1500	1.5 W/m-K	General purpose
Gap Pad 5000S35	5.0 W/m-K	High performance
Gap Pad TGP 10000	10.0 W/m-K	Ultra-high conductivity for 5G

The TGP 10000 line represents the current state of the art, achieving 10 W/m-K thermal conductivity in a soft, compliant pad. This is particularly valuable for 5G base station equipment where power densities continue to increase.

Sil-Pad Thermal Pads

Sil-Pad products are reinforced silicone rubber pads providing both thermal transfer and electrical isolation. They’re commonly used for:

• TO-220 and TO-247 package mounting
• Power transistor thermal interface
• Applications requiring defined compression

Sil-Pad K-4 (0.9 W/m-K) remains one of the most widely used thermal pads in power electronics.

Phase Change Materials

Hi-Flow phase change materials melt at operating temperature to minimize interfacial thermal resistance. They’re ideal for:

• CPU and GPU thermal management
• High-end server applications
• Applications requiring rework capability

Phase change materials offer the thermal performance of greases with the cleaner handling of solid pads.

Manufacturing Considerations

Design Guidelines

When laying out boards for Bergquist materials, keep these factors in mind:

Minimum trace width: 0.006 inches (150 µm) is typical, though finer features are possible with some suppliers.

Copper weights: 1 oz to 4 oz copper is standard. Heavier copper (up to 10 oz) is available for high-current applications but affects etching resolution.

Hole sizes: Minimum drilled hole is typically 0.010 inches (250 µm) for plated vias. Non-plated thermal holes can go larger.

Solder mask: Standard liquid photo-imageable solder mask works. White solder mask is popular for LED applications to maximize reflectivity.

Surface finish: HASL (both leaded and lead-free), ENIG, and OSP are all compatible. ENIG is preferred for fine-pitch components and wire bonding.

Assembly Notes

Bergquist materials are compatible with standard SMT processes, but a few considerations apply:

Solder paste: Standard SAC305 or other lead-free alloys work fine. Minimum solder thickness after reflow should be 0.004 inches (100 µm) for proper stress relief.

Reflow profile: Standard lead-free profiles work. The HT series handles peak temperatures up to 325°C per UL 796.

Thermal relief: The excellent thermal conductivity that makes Bergquist attractive also makes hand soldering difficult. Ensure adequate thermal relief on pads if hand rework is anticipated.

Handling: The aluminum substrate is softer than FR4. V-scoring and routing work, but be careful with edge handling to avoid dents.

Material Selection Decision Tree

Not sure which Bergquist material to specify? Here’s my decision process:

Step 1: Determine power density

• Under 2 W/cm²: Consider MP-06503 first
• 2-5 W/cm²: HT-04503 or LTI-04503
• Over 5 W/cm²: HPL-03015

Step 2: Check voltage requirements

• Under 500 VAC working voltage: 3-mil dielectric okay
• 500-1000 VAC: Use 6-mil dielectric minimum
• Over 1000 VAC: Consider 9-mil or multilayer construction

Step 3: Evaluate operating temperature

• Standard (-40°C to +105°C): MP or LTI series
• Extended (up to +140°C): HT series only

Step 4: Consider cost constraints

• Cost-sensitive: MP-06503
• Performance-critical: HPL-03015 or HT-07006
• Balanced: LTI-04503

Resources and Technical Documentation

Official Documentation

TCLAD (the current owner of Bergquist Thermal Clad technology) maintains technical resources at:

• Company website: www.tclad.com
• Technical support email: sales.us@tclad.com
• Phone: +1 715 262 5898

TCLAD offers design support services including thermal simulation assistance and material selection guidance. Their engineering team includes many staff from the original Bergquist Company with decades of application experience.

Datasheet Sources

Several distributors stock Bergquist materials and provide datasheets:

• Digi-Key: Thermal Clad selection guide and individual material datasheets available at digikey.com
• Newark/Farnell: Full product range with specifications
• Mouser Electronics: Extensive Bergquist TIM catalog
• MCL PCB Resources: Archived Bergquist datasheets (useful for legacy part numbers)

When downloading datasheets, verify the revision date. Specifications have remained stable, but newer documents include additional application guidance.

Design Resources

• IPC-2152: Standard for determining current carrying capacity in PCBs (includes thermal considerations)
• IPC-4101: Specification for base materials—useful for understanding material classifications
• Thermal simulation: FloTHERM and similar tools have Bergquist material libraries. Request material property files from TCLAD if your simulation tool needs custom input.

PCB Fabrication Sources

Several manufacturers specialize in Bergquist materials:

• TCLAD Inc. (direct from the source, Prescott, WI, USA)
• TCLAD Europe GmbH (European operations)
• Various China-based manufacturers maintain Bergquist material inventory

When selecting a fabricator, verify they have actual Bergquist material in stock—some suppliers substitute alternative materials without disclosure. Request material certificates with your order and verify the Bergquist/TCLAD branding on incoming panels.

Additional Technical Resources

For those wanting deeper technical understanding:

• Thermal Clad Selection Guide (available from Digi-Key): Comprehensive 26-page guide covering all dielectric grades, design rules, and assembly recommendations
• IMS Design Handbook from TCLAD: Covers advanced topics including multi-layer constructions and specialty applications
• Application notes covering specific industries: automotive, LED lighting, power electronics

Frequently Asked Questions

What’s the difference between Bergquist and generic aluminum PCB?

Bergquist Thermal Clad uses a proprietary polymer-ceramic dielectric engineered for optimal thermal and electrical performance. Generic aluminum PCBs often use standard epoxy prepreg as the dielectric, which has 3-5x lower thermal conductivity. The Bergquist dielectric also provides better high-temperature stability and more consistent lot-to-lot performance.

You’ll see this difference most clearly in thermal impedance specifications—Bergquist publishes guaranteed values while generic materials often lack this data or show significant variation between production lots. For mission-critical applications where thermal performance must be predictable, the traceability and consistency of genuine Bergquist materials justifies the premium pricing.

Can Bergquist PCBs be multilayer?

Yes, but with limitations. Standard Thermal Clad is single-sided (components on one side only). Double-sided constructions are possible using Bergquist’s Bond-Ply materials, which allow laminating multiple circuit layers. True multilayer metal core PCBs (4+ layers) exist but are specialized products. For most high-power applications, single-sided designs work well since the primary heat source is usually on one side of the board.

How does Bergquist material affect PCB cost?

Bergquist materials typically cost 5-10x more than equivalent FR4 per square inch. However, total system cost often favors Bergquist because you can eliminate separate heat sinks, reduce thermal interface materials, and simplify mechanical assembly. The reliability improvement can also reduce warranty costs significantly. Run a total cost of ownership analysis for your specific application rather than comparing only PCB price.

Is Bergquist PCB suitable for high-frequency applications?

Bergquist materials have a dielectric constant around 6-7, which is higher than typical RF substrates (Rogers materials run 2.5-3.5). This makes them less ideal for RF applications above a few hundred MHz. For LED drivers and power conversion operating below 500 kHz, the dielectric properties are fine. If you need both high-frequency performance and thermal management, consider hybrid constructions with Rogers material for RF sections and Bergquist for power sections.

What happened to Bergquist Company?

Henkel acquired The Bergquist Company in 2014. In 2021, Polytronics Technology Corporation purchased the Thermal Clad division and formed TCLAD Inc. The PCB manufacturing facility remains in Prescott, Wisconsin, with the same equipment and much of the same personnel. Part numbers and specifications have remained consistent through these ownership changes. TCLAD continues developing new materials while maintaining the legacy product line.

Note that Henkel retained the thermal interface materials business (Gap Pads, Sil-Pads, Hi-Flow products), so those products are still available under the Bergquist brand through Henkel. Only the Thermal Clad IMS/MCPCB products transferred to TCLAD.

Conclusion: Selecting the Right Bergquist Material

After years of specifying these materials across dozens of projects, here’s my practical summary:

For most LED applications: Start with MP-06503. It offers the best balance of thermal performance and cost. Only step up to HPL-03015 if your thermal budget genuinely requires it.

For power electronics: HT-04503 should be your baseline. The higher Tg (150°C vs 90°C) provides margin for the inevitable thermal excursions in power circuits.

For automotive or harsh environments: Stick with HT series exclusively. The qualification data and temperature cycling performance justify the modest cost premium.

For prototyping: Work with a supplier who stocks multiple Bergquist grades. Being able to switch materials without changing suppliers accelerates development.

The thermal management landscape continues evolving. Wide-bandgap semiconductors (SiC and GaN) increase power density further, making effective thermal management even more critical. Bergquist materials have proven themselves over 30+ years in demanding applications—that track record provides confidence when designing your next high-power system.