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Notes: For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.
How to Read a Bergquist Thermal Clad Datasheet: Engineer’s Guide
Every Bergquist Thermal Clad datasheet covers the same four property blocks: thermal, electrical, mechanical, and environmental. The problem is that most engineers opening one of these documents for the first time either zero in on a single number — thermal conductivity — and ignore the rest, or get overwhelmed by the ASTM test method references and do not extract the design-critical values they actually need. Both approaches lead to problems in production.
This guide walks through each section of a Bergquist Thermal Clad datasheet in the order you should read it as a design engineer. By the end, you will know which numbers matter for your specific application, what the test methods behind those numbers actually measure, and how to translate datasheet values into real-world design decisions. For background on the Bergquist product family and how these dielectric grades are applied in MCPCB designs, start with the Bergquist PCB overview before returning to the datasheet detail here.
Why the Bergquist Thermal Clad Datasheet Requires Careful Reading
Bergquist Thermal Clad datasheets are compact — typically two pages per dielectric grade — but every value on those two pages is an engineering decision point. The material has been in production for decades, and the datasheet format reflects that: it is written for engineers who already understand IMS PCB construction and need to confirm whether a specific grade meets their design requirements, not for someone learning what thermal conductivity means.
The core principle behind every Thermal Clad product is stated in each datasheet header: the technology of Thermal Clad resides in the dielectric. That single line is the most important context for reading these documents. You are not evaluating a substrate — you are evaluating a dielectric layer whose properties determine every thermal and electrical performance outcome of the finished board. The aluminum or copper base below it, and the copper circuit layer above it, are variables you control separately. The dielectric is what the datasheet is characterising.
Step 1: Identify the Grade and Understand What It Is Optimised For
Before reading any values, confirm which of the four production Thermal Clad grades you are looking at. The grade name encodes both the dielectric family and the thickness:
HPL-03015 — High Power Lighting, 3 mils (76 µm) nominal in the grade name, actual production dielectric at 0.0015″ (38 µm). Optimised for maximum thermal conductivity. Used in COB LED arrays, matrix LED headlamps, UV curing, and high-power horticultural fixtures where power density drives the selection.
HT-04503 — High Temperature, 4.5 mils, 3 oz copper. Balanced grade for applications with elevated ambient temperature and moderate dielectric breakdown requirements. Motor drives, inverters, outdoor LED fixtures, industrial power stages.
HT-07006 — High Temperature, 7 mils, 6 oz copper. Thickest standard HT dielectric, highest breakdown voltage in the HT family. Used wherever 400–800 V bus voltage is present or where the operating environment includes long-term sustained heat exposure above 100 °C.
MP-06503 — Multi-Purpose, 6.5 mils, 3 oz copper. General-purpose grade for commercial and residential LED lighting, HVAC, signage, and any application where thermal margins are comfortable and cost efficiency matters.
The grade name tells you the design intent. If you are looking at an HPL datasheet for a 600 V bus inverter application, you already know before reading a single value that you are looking at the wrong grade.
Step 2: Read the Thermal Properties Section First
Thermal Conductivity
Thermal conductivity is reported in W/m·K and measured per ASTM D5470. This is the property most engineers look for first, and for good reason — it sets the theoretical ceiling on how well the dielectric can transfer heat. However, it is not the number you use directly in thermal calculations.
HPL-03015 reports 3.0 W/m·K. HT-04503 reports 2.2 W/m·K. HT-07006 reports 2.2 W/m·K. MP-06503 reports 1.0 W/m·K. These values are measured on the bulk dielectric material in a standardised test configuration. In your actual board, the effective thermal performance is determined by the thermal resistance — not the conductivity.
Thermal Resistance: The Number You Actually Use in Design
Thermal resistance (°C·in²/W or °C·cm²/W) is measured per ASTM D5470 on the complete laminate construction — the dielectric plus bonded copper foil — and is the value you should use in your junction temperature calculations. It integrates both the thermal conductivity of the dielectric and its thickness into a single, directly applicable design parameter.
HPL-03015 reports 0.02 °C·in²/W. This is the headline performance figure — the lowest thermal resistance of any standard production MCPCB dielectric. Translated into a design calculation: for a 5 mm × 5 mm component pad at 3 W dissipation, the dielectric thermal resistance contribution is approximately 1.2 °C — negligible relative to the component’s junction-to-case resistance and the heatsink resistance.
Table 1: Bergquist Thermal Clad Datasheet Thermal Properties — All Four Grades
Grade
Thermal Conductivity (W/m·K)
Thermal Resistance (°C·in²/W)
Glass Transition (Tg)
Max Operating Temp
Max Soldering Temp
HPL-03015
3.0
0.02
185 °C
150 °C
325 °C
HT-04503
2.2
0.05
>170 °C
140 °C
325 °C
HT-07006
2.2
~0.10
>170 °C
140 °C
325 °C
MP-06503
1.0
~0.22
~130 °C
130 °C
288 °C
Glass Transition Temperature (Tg) and What It Means for Your Design
Tg is the temperature at which the dielectric transitions from a rigid glassy state to a softer rubbery state. Above Tg, the dielectric’s mechanical properties change significantly — it becomes more compliant, which increases CTE-driven stress on solder joints and trace adhesion. Operating continuously above Tg is not the design intent; Tg is the ceiling on the practical operating environment.
HPL-03015’s Tg of 185 °C is notably high for an organic dielectric. The HT grades both exceed 170 °C. MP-06503 at approximately 130 °C is in line with standard high-Tg FR-4, which means it is not suitable for applications where board or ambient temperatures regularly approach or exceed 130 °C.
The maximum operating temperature listed separately is a conservative UL-derived figure representing the long-term continuous rating. Do not confuse it with Tg — a board operating at 140 °C continuous on an HT grade is within spec, not at its glass transition.
Step 3: Read the Electrical Properties Section — More Critical Than Most Engineers Realise
The electrical properties section of a Bergquist Thermal Clad datasheet is where most engineers underinvest their reading time. For low-voltage LED and 12–48 V power supply applications this is a reasonable tradeoff. For anything involving a 400 V or 800 V bus, EV charging infrastructure, or mains-referenced power stages, these values determine whether the board is safe to operate.
Dielectric Strength
Dielectric strength is reported in V/mil (and kV/mm) measured per ASTM D149. HPL-03015 reports 2,000 V/mil (75 kV/mm). At 38 µm (1.5 mil) dielectric thickness, the calculated DC withstand voltage for HPL is approximately 3,000 V — well above the 2.5 kVAC breakdown voltage listed as the tested value on the datasheet.
This distinction matters: dielectric strength in V/mil is a materials characterisation value. The breakdown voltage on the datasheet (2.5 kVAC for HPL) is the tested performance of the actual laminate at the specified thickness. Use the breakdown voltage figure in your design, not the V/mil number extrapolated to your own thickness.
Operating Voltage Ratings
The HPL-03015 datasheet explicitly lists operating voltage ratings: 120 VAC continuous, 170 VDC continuous, 260 VDC peak recurring. These are not calculated — they are tested and UL-derived ratings for the dielectric at production thickness. An HPL board operating at 48 VDC is well within these ratings. An HPL board on a 400 VDC bus is not.
For high-voltage applications, the HT-07006 grade at 178 µm dielectric thickness provides substantially higher breakdown voltage headroom. The HT-07006 datasheet describes it as featuring even higher dielectric breakdown characteristics than HT-04503. If you need to confirm specific voltage ratings for your bus voltage and safety margin, contact Henkel’s (formerly Bergquist) applications engineering team directly — the datasheet operating voltage figures are for the standard laminate construction and may not cover every custom thickness variant.
HPL-03015 reports 925 pF/in² (140 pF/cm²) at the standard dielectric thickness. This value matters for two design scenarios: high-frequency switching designs where the dielectric capacitance between the copper circuit layer and the metal base appears as a parasitic in the circuit, and HiPot (high potential) testing during production, where all IMS boards behave as parallel plate capacitors during the test. The HiPot current during testing is capacitive — understanding the board’s capacitance per unit area allows you to set the correct test current limits and avoid false-fail conditions from displacement current being misread as leakage.
Step 4: Mechanical Properties — Dielectric Thickness and Peel Strength
The mechanical properties block in a Bergquist Thermal Clad datasheet contains two values that matter directly to fabrication: dielectric thickness and peel strength.
Dielectric Thickness
Dielectric thickness is specified in both inches and micrometres. HPL-03015 at 0.0015″ (38 µm) is the thinnest standard Thermal Clad dielectric. This thinness is what delivers the low thermal resistance, but it also creates constraints: the fabricator needs to handle the laminate carefully during lamination pressing to avoid dielectric thinning or void formation under aggressive cure conditions.
For the HT grades and MP grade, the thicker dielectrics (114–178 µm) are more forgiving in lamination processing but deliver higher thermal resistance. The relationship is direct: thermal resistance is approximately proportional to dielectric thickness divided by thermal conductivity (t/k). When you need to choose between HT-04503 (114 µm, 2.2 W/m·K) and HT-07006 (178 µm, 2.2 W/m·K), the thermal resistance difference is significant — the HT-04503 is thermally more efficient, but HT-07006 provides more voltage isolation headroom.
Peel Strength
Peel strength (reported in lb/in or N/mm, tested per ASTM D3165 or IPC TM-650 2.4.8) quantifies the adhesion between the copper circuit layer and the dielectric. A value of 6–8 lb/in (1.0–1.4 N/mm) is typical for Thermal Clad grades. This value matters for manufacturing reliability: trace adhesion under thermal cycling, resistance to trace lifting during solder assembly, and long-term adhesion in high-humidity environments all trace back to peel strength.
The Henkel (Bergquist) datasheet for the Thermal Clad TIC_TIP grades includes storage conditions that matter if you are holding bare laminate before fabrication: optimal storage at 5 to 25 °C with a 12-month shelf life in the unopened container. This is not boilerplate — ceramic-filled polymer dielectrics can absorb ambient moisture under poor storage conditions, and a moisture-compromised dielectric laminate will produce voids during the lamination press cycle when residual moisture vaporises under heat and pressure.
For boards that have been fabricated but not immediately assembled, the same moisture caution applies in reverse: store finished bare IMS boards in moisture barrier bags with desiccant. A board exposed to ambient humidity for weeks before reflow assembly can delaminate during the solder reflow profile, even if the original laminate was stored correctly.
Choosing the Right Grade: A One-Page Decision Matrix
After reading each section of the Bergquist Thermal Clad datasheet, the practical output should be a grade selection decision. The following decision matrix reflects the design intent behind each grade based on the datasheet values read against common application requirements.
5 FAQs: Reading the Bergquist Thermal Clad Datasheet
Q1: Why does the HPL-03015 datasheet list thermal conductivity as 3.0 W/m·K but the thermal resistance as 0.02 °C·in²/W? How are these related?
Thermal conductivity (W/m·K) and thermal resistance (°C·in²/W) measure different things and are used differently in design. Thermal conductivity is a bulk material property — independent of thickness, it describes how readily heat flows through a unit cube of the material. Thermal resistance is a construction-dependent property that combines conductivity with thickness: R = t / (k × A), where t is thickness, k is conductivity, and A is area. The 0.02 °C·in²/W figure for HPL-03015 already accounts for the 38 µm dielectric thickness and is measured on the actual laminate per ASTM D5470. For your junction-temperature calculations, always use the thermal resistance figure from the datasheet, not the conductivity. The conductivity value is useful for comparing materials relative to each other and for calculating expected performance at non-standard dielectric thicknesses.
Q2: The datasheet lists an operating voltage of 120 VAC for HPL-03015. Can I use this grade on a 48 VDC bus?
Yes, without reservation. The 120 VAC continuous rating is a UL-derived conservative long-term figure for the material at 38 µm thickness. 48 VDC is well below both the continuous DC rating (170 VDC) and the peak rating (260 VDC) listed in the HPL datasheet. The HPL grade is used extensively in 12 V, 24 V, and 48 V LED and power supply designs. The operating voltage ratings in the datasheet are maximums, not minimums — any application voltage below those figures is within specification.
Q3: All four Thermal Clad grades list UL 94 V-0 flammability. Does this affect which grade I need for UL-listed end products?
V-0 means the material self-extinguishes within 10 seconds when exposed to flame and does not drip burning particles. All four Bergquist Thermal Clad grades meet this requirement, so flammability rating is not a differentiator between grades. For a UL-listed end product, you also need to confirm that the specific board construction — the grade, copper weight, base metal thickness combination — is covered under Bergquist/Henkel’s UL recognition. Bergquist maintains UL file certifications for specific grade and thickness combinations. If you are using a non-standard construction, confirm UL coverage explicitly with Henkel applications engineering before committing the design to UL listing.
Q4: The HT-07006 datasheet says it features even higher dielectric breakdown characteristics than HT-04503. Does that mean I can always substitute HT-07006 for HT-04503?
Not without reviewing the thermal resistance impact. HT-07006 at 178 µm delivers higher breakdown voltage than HT-04503 at 114 µm, and both grades have the same 2.2 W/m·K thermal conductivity. But because the HT-07006 dielectric is 56% thicker, its thermal resistance is proportionally higher — approximately 2× HT-04503 at equivalent copper weight. If your design thermal margin is tight and you switch from HT-04503 to HT-07006 for the additional voltage headroom, re-run your junction temperature calculation with the higher thermal resistance value. The extra isolation is only free if your thermal budget allows it.
Q5: What does the 325 °C maximum soldering temperature mean, and does it matter for standard lead-free SMT assembly?
The 325 °C / 60 second UL 796 rating in the HPL and HT datasheets confirms compatibility with eutectic gold-tin (AuSn 80/20) solder, which processes at approximately 300–320 °C. For standard SAC305 lead-free reflow, typical peak temperatures are 245–260 °C — comfortably below the 325 °C material limit. The 288 °C rating for MP-06503 also covers standard lead-free SAC305 reflow without issue, but is not rated for AuSn eutectic solder processes. In practice, the soldering temperature limit is only a differentiating factor if your assembly process uses AuSn for die attach or specific high-reliability solder joints. For standard SMT assembly on any Thermal Clad grade, the peak reflow temperature is determined by your component specifications, not the dielectric’s material limit.
Summary: How to Extract Maximum Value from a Bergquist Thermal Clad Datasheet
Reading a Bergquist Thermal Clad datasheet productively comes down to a five-step discipline. Identify the grade and confirm its intended application matches yours. Extract the thermal resistance — not just the conductivity — and use it in your junction temperature calculation. Check the breakdown voltage against your working bus voltage with a safety margin. Verify that the Tg and maximum operating temperature exceed your worst-case ambient plus expected component self-heating. Confirm that the soldering temperature rating covers your assembly process.
Every number on those two pages exists because a design decision depends on it. The grade selection matrix and the direct datasheet links in this article provide the fastest path from datasheet to the right material selection for your application.
For a broader overview of how Bergquist Thermal Clad grades are applied across LED lighting, automotive, and power electronics designs, visit our Bergquist PCB reference page.
Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Notes: For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.
