Bergquist MCPCB for Power Electronics: Motor Drives, Converters & Inverters

Ask any power electronics engineer what keeps them up at night, and thermal management is somewhere in the top three. It does not matter whether you are designing a three-phase motor drive at 5 kW, a bidirectional DC-DC converter for an EV charging station, or a solar inverter pushing efficiencies past 98% — the common thread is heat, and how to move it away from semiconductors fast enough to keep the system alive.

MCPCB power electronics design has matured to the point where aluminum or copper-core boards are not a premium option but a baseline expectation for any design with sustained power dissipation above 2–3 W per component. Within that space, Bergquist Thermal Clad has earned a position as one of the most specified materials platforms globally — and for reasons that go beyond marketing. This article unpacks why, covers the Bergquist dielectric selection logic for motor drives, converters, and inverters specifically, and gives you the data you need to make the right call on your next power board.

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Why Standard FR-4 Fails in High-Power Electronics

Before getting into Bergquist specifics, it is worth being direct about where FR-4 breaks down. Traditional FR-4 printed circuit boards struggle under demanding power electronics conditions, with limited thermal conductivity around 0.3 W/m·K and copper traces that overheat under sustained high-current operation. These limitations force engineers to either compromise on power density or risk premature component failure.

In practical terms, that 0.3 W/m·K figure means that even a dense array of thermal vias — the traditional FR-4 workaround — still pushes heat through a poor conductor. The via copper conducts well, but the surrounding epoxy does not, and in concentrated high-dissipation layouts (think IGBT gate driver stages, SiC MOSFET modules, or full-bridge converter switch clusters), the thermal via approach runs out of runway fast.

Motor drives, inverters, and industrial control circuits generate significant heat while conducting currents that can exceed 100 amperes in concentrated areas. Switching converters and inverters for power electronics require metal core PCBs to manage substantial heat dissipation from components like inductors and FETs. Motor drives work under challenging operating temperatures, and metal core PCBs allow efficient thermal management in the tightly packed drives. The math is simple: if your thermal simulation demands 50+ thermal vias per MOSFET footprint and you still cannot meet the 150 °C junction temperature ceiling, it is time to change the substrate, not the via count.

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What Makes MCPCB the Right Platform for Power Electronics

A metal core PCB replaces the conventional glass-epoxy dielectric core with a metal substrate — almost always aluminum for cost-sensitive industrial and commercial power designs, copper for the most thermally demanding applications where space is genuinely critical. The board stack is three layers at its simplest: the copper circuit layer on top, a thermally conductive and electrically insulating dielectric layer in the middle, and the metal baseplate at the bottom.

The difference in real-world thermal performance is substantial. MCPCB power electronics boards offer thermal conductivity in the range of 1–2 W/m·K for aluminum-based designs, compared to 0.25–0.3 W/m·K for FR-4. Metal core PCB technology enables integration of electronic components and systems with higher power densities by effectively managing dissipated heat. Copper base MCPCB becomes necessary when power density exceeds aluminum’s spreading capacity or when the application requires maximum thermal performance. The copper base provides approximately 385 W/m·K thermal conductivity and superior flatness for precision component mounting.

Beyond raw conductivity, using an MCPCB in a power electronics design delivers a built-in mechanical benefit: the metal baseplate bolts directly to an external heatsink or chassis cooling structure. Metal-backed construction enables direct mounting of power modules to the PCB with thermal interface material providing low-resistance heat transfer to the base plate, which then bolts directly to cooling systems. That eliminates one thermal interface compared to the typical FR-4 + clip-on heatsink approach, and every eliminated interface reduces system thermal resistance.

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Bergquist Thermal Clad: Engineering Logic for Power Electronics

The Bergquist PCB Thermal Clad platform, now maintained under the Henkel umbrella, is built around the idea that the performance of an insulated metal substrate lives entirely in its dielectric. The technology of Thermal Clad resides in the dielectric layer — not the copper, not the aluminum plate, but the thin bonding material between them.

For power electronics engineers, this is a useful frame. When you are evaluating two competing MCPCB offerings and both claim 1.0 mm aluminum at 1 oz copper, the dielectric is the variable that determines whether your IGBT footprint runs at 110 °C or 135 °C. Bergquist Thermal Clad gives engineers four dielectric families to work with, each engineered for a different point on the thermal performance-cost curve.

Henkel’s LOCTITE Bergquist thermal management products have been trusted for decades, and in the motor drives and power conversion space, the HT series in particular has become essentially the reference standard for high-temperature MCPCB applications. Thermal interface materials like Bergquist GAP PADs help protect against the effects of heat, providing a low thermal resistance dielectric interface between power-generating components and their heatsinks.

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Bergquist Dielectric Grades for Power Electronics: Full Comparison

The four Thermal Clad dielectric series are High Power Lighting (HPL), High Temperature (HT), Low Modulus (LM), and Multi-Purpose (MP). For power electronics — motor drives, converters, inverters — the decision almost always comes down to choosing between HT-07006, HT-04503, and MP-06503, with LM appearing in specific mechanical stress situations. Here is how they compare:

Table 1: Bergquist Thermal Clad Dielectric Series for Power Electronics

Dielectric	Thermal Conductivity (W/m·K)	Thickness	Tg (°C)	Dielectric Strength	Power Electronics Fit
HPL-03015	~4.1	0.0015″ (38 µm)	185	Very High	LED stages only; too thin for most power switch layouts
HT-07006	~2.2	0.0070″ (178 µm)	>170	Very High	Motor drives, inverter stages, high-temp converters
HT-04503	~2.2	0.0045″ (114 µm)	>170	Very High	DC-DC converters, gate driver boards, EV BMS
MP-06503	~1.0	0.0065″ (165 µm)	~130	High	Low-power converters, HVAC drives, cost-driven designs
LM Series	~1.0–1.5	Various	~130	High	CTE-stress relief, large ceramic packages, flex attach

HT dielectrics are UL solder-rated at 325 °C for 60 seconds, enabling Eutectic Gold/Tin solders — a relevant detail if your power module assembly uses AuSn die attach. MP-06503 at 1.0 W/m·K is still a dramatic improvement over FR-4, but its lower Tg of approximately 130 °C limits it to applications where the ambient temperature never sustains above 85 °C.

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Motor Drives: Thermal Challenges and Bergquist Solution

Three-phase motor controllers switch currents between 20 and 200 amperes at frequencies from several kilohertz to tens of kilohertz, generating both conduction losses in power semiconductors and switching losses during transistor transitions. The PCB design must handle the three-phase power switching while providing precise timing control.

For BLDC and AC drive applications, the IGBT or MOSFET bridge generates the majority of the thermal load. Modern gate driver ICs provide fast switching with integrated protection, but even at 98% efficiency, a 10 kW motor drive is dissipating 200 W. Concentrated into six switch positions over a typical 150 mm × 100 mm board, that is significant localized heat flux.

In this environment, HT-07006 or HT-04503 is the correct Bergquist choice. The 2.2 W/m·K conductivity reduces the thermal resistance of the dielectric layer by more than 2× compared to MP-grade, and the >170 °C Tg provides adequate margin for sustained operation at elevated ambient temperatures. Modern motor drives are integrating more complex power devices to manage growing energy efficiency requirements, and the next-generation motor controller requires a thermal interface material to manage new performance challenges and higher power densities. Any thermal material selected had to meet challenging metrics: electrical isolation with high dielectric strength greater than 5,000 V and low thermal resistance.

Table 2: Motor Drive MCPCB Design Parameters

Drive Class	Typical Power	Switch Current	Recommended Bergquist Grade	Baseplate Material
Fractional HP BLDC (<500 W)	<500 W	<10 A	MP-06503 or HT-04503	Aluminum
Industrial servo (0.5–5 kW)	500 W–5 kW	10–50 A	HT-04503 or HT-07006	Aluminum
Mid-power AC drive (5–30 kW)	5–30 kW	50–150 A	HT-07006	Aluminum or copper
High-power traction drive (>30 kW)	>30 kW	>150 A	HT-07006 + copper MCPCB	Copper
SiC-based inverter (EV traction)	50–250 kW	100–600 A	HT-07006 copper MCPCB	Copper

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DC-DC Converters: Where Bergquist Thermal Clad Earns Its Specification

Switch-mode power supplies and DC-DC converters represent a massive category of power electronics where MCPCB design delivers consistent, measurable results. The challenge in converters is not always peak heat — it is sustained heat under continuous load. A 3 kW bidirectional DC-DC converter running at 95% efficiency with no duty cycle variation generates 150 W continuously. That has to go somewhere without cooking the MOSFETs or transformer core.

Bergquist Bond-Ply products have been identified as a single material solution for reducing parts complexity and cost in power supply designs, with solutions helping clients reduce production costs by 20–30%. In converter applications, Bergquist HT-04503 is frequently the specified dielectric because its 114 µm thickness gives better dielectric breakdown headroom than HPL while still delivering 2.2 W/m·K conductivity. HT-04503 is described as a go-to choice for high-performance power converters, where maintaining efficiency under load is key.

The 48V/12V DC-DC converters used in automotive mild-hybrid architectures deserve a specific mention. These converters operate at ambient temperatures up to 105 °C in engine-bay or under-hood mounting locations, switching at frequencies in the 100–500 kHz range with GaN or SiC devices. The high junction temperature capability of GaN (up to 150 °C) and SiC (up to 175 °C) means the substrate needs to keep pace. HT-grade Bergquist dielectrics, with their >170 °C Tg, remain stable well past the thermal range where MP-grade material starts to soften.

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Solar and Industrial Inverters: MCPCB at Scale

Inverter PCB designs for solar, UPS, and motor drive applications benefit significantly from the thermal management that power MCPCB provides. These circuits convert DC power to AC through rapid switching, with power levels ranging from several hundred watts to megawatt-scale industrial systems. The concentration of heat in power modules requires efficient extraction to maintain switching frequency and prevent thermal runaway.

Inverters with MCPCBs can achieve efficiency rates exceeding 98%, compared to lower efficiencies in systems using traditional PCBs. That improvement comes primarily from the ability to operate switches at lower junction temperatures, which reduces on-state resistance (particularly for SiC and GaN devices whose on-resistance has a positive temperature coefficient) and improves thermal cycling lifetime.

For solar string inverters and residential energy storage inverters — typically 3–20 kW with SiC MOSFET topology — HT-07006 on aluminum is the standard Bergquist choice. The thicker dielectric at 178 µm provides robust isolation for the DC bus voltage, and the 2.2 W/m·K conductivity handles the continuous load profile typical of solar applications. Industrial grid-tied inverters above 30 kW frequently move to copper MCPCB with HT-07006 dielectric to handle the higher power density while maintaining the isolation performance needed for 400–1,000 VDC bus voltages.

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Copper Weight and Baseplate Selection for Power Electronics MCPCB

One of the most common specification mistakes in MCPCB power electronics designs is undercalling copper weight. The thermal benefit of the metal core is only realized if the copper circuit layer can actually spread heat laterally to the dielectric-baseplate interface. Thin copper creates a thermal pinch point immediately below a concentrated power device.

For motor drives and inverters, 2 oz copper (70 µm) is a practical minimum, with 3 oz (105 µm) preferred for anything above 10 A continuous per trace. 3 oz copper traces carry approximately 2× more current than 1 oz traces for the same trace width, and the reduction in resistive heating (I²R) compounds the benefit of the MCPCB substrate itself.

Table 3: Copper Weight Selection for Power Electronics MCPCB

Application Current Range	Recommended Copper Weight	Notes
<5 A continuous	1 oz (35 µm)	Standard, cost-effective
5–20 A	2 oz (70 µm)	Preferred for gate driver and auxiliary supply traces
20–50 A	3 oz (105 µm)	Motor phase traces, converter switch nodes
50–100 A	4–6 oz (140–210 µm)	Heavy power bus traces, bus bars alternatives
>100 A	Bus bars + MCPCB	Press-fit pins or eyelets; MCPCB as thermal spreader

Aluminum remains the default baseplate for power electronics MCPCB in the 1–30 kW range, offering moderate thermal conductivity around 237 W/m·K at a cost premium over FR-4 that is manageable in production volumes. Copper baseplates at approximately 385 W/m·K are justified when the baseplate itself needs to interface with a precision liquid cold plate, a vapor chamber, or a situation where the total junction-to-coolant thermal resistance budget is extremely tight.

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Via Design and Interconnect Constraints in Power MCPCB

Standard vias cannot go through the metal core — this is a hard manufacturing constraint that trips up engineers transitioning from FR-4 multilayer designs. For multi-layer needs, the solution is local FR-4 buildups, microvias, or hybrid MCPCB-plus-FR-4 assemblies. For complex motor controller designs with both a power stage and a signal processing section, hybrid designs — MCPCB for the hot zone plus FR-4 or rigid-flex for the control — joined by flex or FFC often provide the best performance per zone without fighting physics.

In single-layer power MCPCB designs (the most common configuration for motor drives and converter power stages), interconnect between the gate drive circuit and the power switches needs careful trace routing. Short, wide paths from hot components to copper pours should minimize thermal bottlenecks. High-current jumpers benefit from press-fit pins, eyelets, or bus bars for anything above 50 A.

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MCPCB Power Electronics Application Matrix

The following table maps common power electronics applications to the appropriate Bergquist dielectric and MCPCB baseplate configuration, based on typical operating parameters.

Table 4: Power Electronics Application to Bergquist MCPCB Specification

Application	Power Range	Max Ambient	Bergquist Dielectric	Baseplate	Copper Weight
BLDC motor controller	<1 kW	85 °C	MP-06503 or HT-04503	Aluminum	1–2 oz
Industrial servo drive	1–10 kW	85–105 °C	HT-04503	Aluminum	2–3 oz
AC variable frequency drive	5–30 kW	85–105 °C	HT-07006	Aluminum	3 oz
Automotive DC-DC (12V/48V)	1–5 kW	105–125 °C	HT-07006	Aluminum	2–3 oz
Residential solar inverter	3–10 kW	85 °C	HT-07006	Aluminum	2–3 oz
Commercial solar inverter	10–50 kW	85 °C	HT-07006	Aluminum/Copper	3–4 oz
EV on-board charger (OBC)	3–22 kW	105 °C	HT-07006	Aluminum	3 oz
EV traction inverter (SiC)	50–300 kW	125 °C	HT-07006	Copper	3–6 oz
UPS inverter module	1–20 kW	85 °C	HT-04503	Aluminum	2–3 oz
Wind turbine converter	100 kW+	85 °C	HT-07006	Copper	4–6 oz

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Thermal Resistance Calculation: Why Bergquist HT Outperforms MP in Practice

To put concrete numbers on the dielectric grade decision, consider a SiC MOSFET in a TO-247 package dissipating 15 W, mounted on an aluminum MCPCB with a 5 mm × 8 mm die footprint. We compare HT-04503 and MP-06503 under identical conditions:

HT-04503 (2.2 W/m·K, 114 µm): R_dielectric = 0.000114 / (2.2 × 0.00004) = 1.29 °C/W

MP-06503 (1.0 W/m·K, 165 µm): R_dielectric = 0.000165 / (1.0 × 0.00004) = 4.13 °C/W

At 15 W dissipation, the dielectric temperature difference at the die footprint is approximately 42 °C. With an HT-04503 board, the MOSFET junction might sit at 130 °C. With MP-06503, it reaches 172 °C — well past the device’s rated maximum. Selecting the correct dielectric is not a material science preference; it is a design requirement.

Table 5: Bergquist Dielectric Thermal Resistance Comparison (5 mm × 8 mm Footprint, 15W Dissipation)

Dielectric	k (W/m·K)	Thickness	R_dielectric (°C/W)	ΔT at Junction (°C)
HPL-03015	4.1	38 µm	0.46	6.9
HT-04503	2.2	114 µm	1.29	19.4
HT-07006	2.2	178 µm	2.02	30.3
MP-06503	1.0	165 µm	2.06	30.9
FR-4 (ref)	0.25	100 µm	12.5	187.5

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Assembly and Process Considerations for Power MCPCB

The metal core significantly increases the thermal mass of the board. This has a practical consequence during reflow assembly: the board absorbs substantially more heat during the reflow cycle, requiring tuned soldering profiles and adjusted stencil apertures to ensure proper wetting of power pads without overheating smaller passives on the same board. Define powered thermal tests — steady-state temperature, ramp-and-soak cycling — and electrical safety checks (hipot across the dielectric) during design validation.

Thermal interface material between the MCPCB backside and the chassis or heatsink is the final link in the thermal chain. Phase-change thermal interface materials are often the preferred choice for heat management in drives — particularly in the inverter between powerful IGBT components and heat sinks. Printable and dispensable phase-change thermal compounds allow controlled bondline thicknesses, and thixotropic properties keep materials from flowing out of the interface for maximum thermal performance.

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Useful Resources for MCPCB Power Electronics Engineers

Resource	Content	Link
Bergquist Thermal Clad Selection Guide	Full dielectric comparison, design rules, soldering notes, current carrying capacity charts	Digikey PDF
Bergquist HT-07006 Datasheet	Full spec for the primary power electronics dielectric	MCLPCB PDF
Bergquist HT-04503 Datasheet	Spec sheet for the 3 mil high-temperature dielectric	MCLPCB PDF
Bergquist MP-06503 Datasheet	Multi-purpose grade for cost-driven power designs	MCLPCB PDF
Henkel Industrial Automation Thermal Solutions	Application notes for motor drives and power conversion using Bergquist materials	Henkel.com
IPC-2221B Generic Design Standard	Trace width, current capacity, and thermal design guidelines for PCB engineers	IPC.org
ROHM SiC MOSFET Application Note	Thermal design and gate drive requirements for SiC power devices used on MCPCB	ROHM PDF

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5 FAQs: Bergquist MCPCB for Power Electronics

Q1: At what power level does it make sense to switch from FR-4 with thermal vias to MCPCB for a motor drive?

There is no universal threshold, but a practical rule is this: if your thermal simulation requires more than 20–30 thermal vias per major power device to stay within junction temperature limits, you are probably fighting the substrate. For sustained dissipation above 3–5 W per component in a compact layout — typical of any motor drive above 500 W — MCPCB power electronics design pays off quickly in reduced cooling system cost, smaller heatsinks, and improved reliability lifetime. The 2–4× upfront cost premium over FR-4 is almost always recovered in system-level simplification.

Q2: Can I use Bergquist HT-07006 for a SiC MOSFET-based inverter operating at 800 VDC bus voltage?

HT-07006 has a very high dielectric breakdown voltage, typically well above 3,000 V for the 178 µm dielectric. For an 800 VDC bus with a standard 20× safety margin, you need an isolation rating of at least 16,000 V — which is a board-level creepage and clearance challenge, not a dielectric breakdown question. The dielectric breakdown of HT-07006 comfortably exceeds working voltage requirements; the real design work is ensuring adequate trace-to-baseplate creepage distances at the circuit layer. Always verify your specific lot’s datasheet value and apply your company’s derating policy before committing to a production stackup.

Q3: Is copper-core MCPCB always the right answer for a high-power inverter, or does it create new problems?

Copper base at ~385 W/m·K is genuinely better at spreading heat than aluminum, but it brings three complications: it is heavier (density ~8.9 g/cm³ vs ~2.7 g/cm³ for aluminum), it costs significantly more, and its lower CTE (~17 ppm/°C) is actually closer to the copper circuit layer — which reduces some CTE-mismatch stress. For EV traction inverters above 50 kW where the thermal density mandates it, copper MCPCB with HT-07006 dielectric is the standard approach. For anything below that threshold, evaluate whether a thicker aluminum plate (2.0–3.0 mm vs 1.0–1.6 mm standard) with HT-07006 achieves the same result at lower cost before committing to copper.

Q4: How does Bergquist MCPCB handle the high dV/dt generated by SiC and GaN switching?

High dV/dt (slew rates above 50 V/ns are common in SiC designs) creates displacement currents through the capacitance of the dielectric layer. The dielectric capacitance per unit area increases as thickness decreases, so HPL at 38 µm is significantly more capacitive than HT-07006 at 178 µm. For SiC and GaN power stages, HT-07006 or HT-04503 is therefore preferable to HPL — the additional dielectric thickness reduces parasitic capacitance and the resulting high-frequency noise injection into the baseplate and chassis. This is a less commonly discussed but practically important reason to choose the HT series over HPL for power switching applications, regardless of the thermal conductivity difference.

Q5: What surface finish works best for power electronics MCPCB using Bergquist dielectrics?

ENIG (Electroless Nickel Immersion Gold) is the most widely used surface finish for power electronics MCPCB for three reasons: it provides a flat, solderable surface for large-pad power devices; it handles multiple reflow cycles without degradation; and it is compatible with both solder paste and die-attach adhesive processes. Immersion Silver (ImmAg) is an alternative where cost is tighter and the assembly will go through a single reflow cycle. HASL is generally avoided for power electronics because the uneven surface profile can create voids under large thermal pads, introducing localized thermal resistance that defeats the purpose of specifying a premium Bergquist dielectric.

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Summary: Getting the Most from Bergquist MCPCB in Power Electronics

The MCPCB power electronics design decision is ultimately straightforward once you have the thermal budget in hand. FR-4 with thermal vias is a workaround that works until it does not. Metal core PCB — and specifically Bergquist Thermal Clad — is a first-principles solution that builds thermal performance directly into the substrate.

For the majority of motor drive, converter, and inverter applications, HT-07006 on an aluminum baseplate is the anchor specification: 2.2 W/m·K conductivity, >170 °C Tg, high dielectric breakdown, and UL-rated solder compatibility. HT-04503 offers the same conductivity at a reduced dielectric thickness for designs where the thinner cross-section improves the thermal math. MP-06503 remains viable for cost-driven, lower-temperature applications where thermal margins are comfortable and sustained ambient temperatures stay below 85 °C.

The detail that separates good MCPCB designs from marginal ones is usually not the dielectric grade choice — it is the copper weight, component placement, and thermal interface material selection that follows downstream. Get the dielectric right, then optimize the rest of the thermal stack around it, and the Bergquist platform consistently delivers the junction temperatures your power devices — and your reliability specifications — require.

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For sourcing and technical guidance on Bergquist Thermal Clad MCPCBs, visit the Bergquist PCB resource page.