A solar micro-inverter is a small power-conversion device installed on or near an individual solar panel, rather than routing an entire array through one central inverter. Each micro-inverter converts the direct current (DC) power produced by its own dedicated panel into grid-compatible alternating current (AC) power right at the panel — an architecture often called panel-level power conversion.
This is one of two dominant inverter architectures used in residential solar systems, alongside traditional string inverters, which convert DC to AC for an entire series-connected string of panels from a single central location, typically mounted at ground level or on an exterior wall.
💡READ MORE: Recent news from leading micro-inverter suppliers shows how fast the residential segment is evolving. Enphase has pushed higher-power rooftop systems forward with its new IQ9N residential microinverter, first launched in Europe and then introduced in the U.S., with GaN-based power electronics aimed at improving efficiency and thermal performance.
Residential micro-inverters operate continuously outdoors, where elevated ambient temperatures, direct solar loading, and sealed IP-rated enclosures all work against heat dissipation. Power transistors, magnetics, and control circuitry are packed into a compact footprint, and each of these components generates heat during normal operation, with fewer places for that heat to escape than in a ventilated, ground-mounted central inverter cabinet.
Long-term thermal stability directly affects power conversion efficiency, component lifetime, and overall system reliability — which is why effective thermal management has to be built into the design from the start, not addressed after the fact.
This is exactly the environment one T-Global customer was designing for.
The customer is a solar equipment manufacturer based in North America, working in the energy sector on micro-inverters for residential solar systems. As they worked through their design, they needed a thermal approach that could keep pace with a layout that was still evolving — one that would support design revisions and product validation without adding rework costs or slowing the schedule down.
The objective was to achieve reliable heat dissipation while allowing rapid design iterations, as component layouts and heat source locations continued to evolve throughout development.
For that stage of the project, they wanted a flexible, solid-state thermal solution that could:
T-Global engineered a modular, solid-state alternative built around the TO-220 power transistor — a common package for the switching devices used in micro-inverter power stages. The system pairs a ceramic heat spreader with a thermal pad, giving the customer a stack that conducts heat efficiently while remaining fully field-adjustable.
Heat generated at the power transistor needs a clear route out of the enclosure. In this design, it moves in stages: from the power transistor (the heat source), through the ceramic heat spreader (acting as an electrical insulator), through the thermal pad (which fills the surface irregularities between the heat spreader and the enclosure), into the aluminum enclosure (which acts as the heat sink), and finally out into the surrounding ambient air.
The ceramic heat spreader and thermal pad aren't interchangeable — each plays a distinct, complementary role along that path. The ceramic heat spreader redistributes concentrated heat away from the power transistor while providing electrical isolation and long-term thermal stability. The thermal pad then conforms to surface irregularities between the spreader and the aluminum housing, minimizing interface resistance and enabling efficient heat transfer into the enclosure. Together, the two materials create an efficient thermal path from the power semiconductor to the aluminum housing.
The ceramic heat spreader sits directly against the power device and spreads heat locally before it reaches the pad and heatsink. Key properties include:
Because it's a solid, discrete component rather than a poured compound, the ceramic spreader can be repositioned, swapped, or resized as the board layout changes — a critical advantage during the prototyping and design-validation phase.
The XL-25D/XL-25W ceramic heat spreader is available pre-sized to match industry-standard power device packages, so it drops into existing designs without custom tooling:
| Packaging Spec. | Dimensions (mm) |
|---|---|
| TO-220 | 20 x 14 x 0.635 |
| TO-220 | 20 x 14 x 1.0 |
| TO-220 | 12 x 18.5 x 1.0 |
| TO-247 | 22 x 17 x 0.635 |
| TO-247 | 22 x 17 x 1.0 |
| TO-264 | 28 x 22 x 0.635 |
| TO-264 | 28 x 22 x 1.0 |
| TO-3P | 25 x 20 x 0.635 |
| TO-3P | 25 x 20 x 1.0 |
The TG-A3500 thermal interface pad completes the stack, sitting between the ceramic spreader and the aluminum enclosure. Key properties include:
TG-A3500 thermal pad key properties:
| Property | Value |
|---|---|
| Thermal Conductivity | 3.5 W/m·K |
| Thickness | 0.5 – 8.0 mm |
| Dielectric Breakdown Voltage | 13 kV/mm |
| Hardness | Shore OO 35 |
The real driver of flexibility is T-Global's post-process customization: pads can be die-cut, kiss-cut, or film-cut to precise shapes for a given board layout, reinforced with fiberglass mesh for added stability in high-power applications, and finished with a choice of PET or PI lamination, liner, and adhesive configuration to match assembly and handling requirements. Together, this lets engineers close varying air gaps caused by component tolerances or enclosure design changes, and adapt the pad to a new revision, without redesigning the thermal stack from scratch.
Key Benefits & Core Value
Solid-state Thermal Solution — A fully solid-state stack delivers reliable heat transfer while remaining adjustable throughout development.
Rework-Friendly Assembly — Because components aren't cured or bonded in place, installation and design rework stay simple, even late in the design cycle.
Design Iteration Flexibility — The stack supports changing component layouts and heat source locations as thermal requirements evolve.
De-risked Development — Because the components are discrete and installed rather than cured in place, design teams can validate thermal performance early in the development cycle, catching problems before they reach mass production.
Localized & Custom Agility — The solid-state stack supports low-volume customization and responsive technical support — engineers can adjust heat spreader placement or pad thickness for a specific board revision quickly, without a long lead time.
Accelerated Time-to-Market — Streamlined material adoption — dropping in a standard-sized ceramic spreader that matches common power device packages, paired with a thermal pad sized to fit — helps manufacturers move from prototype to production faster.
For power electronics like solar micro-inverters, where heat source locations and enclosure geometry are still being finalized, a solid-state ceramic spreader + thermal pad system offers three practical advantages during active design work:
Once a design is finalized and ready for high-volume production, potting compounds remain an excellent option for permanently sealing and protecting an assembly against moisture, vibration, and environmental exposure. T-Global offers both solid-state thermal materials and potting compounds, so manufacturers can choose the right material for wherever their product is in its development lifecycle.
A solid-state thermal solution uses discrete, pre-formed components — such as ceramic heat spreaders and thermal pads — to move heat away from electronic components. Because the parts aren't cured or bonded in place, they can be repositioned, resized, or replaced as a design evolves.
A ceramic heat spreader and thermal pad system is well suited to the design and validation phase, when component placement, heat source locations, or enclosure geometry may still change. Because the parts are discrete rather than cured in place, engineers can modify the thermal path quickly during development, helping reduce both cost and time-to-market ahead of finalizing a design for production.
The XL-25D/XL-25W ceramic heat spreader are available in dimensions tailored to standard power packages, including TO-220, TO-247, TO-264, and TO-3P.
T-Global offers a range of post-process services for thermal gap fillers, including multiple cutting methods, reinforcement options, lamination choices, liner selection, adhesive configuration, and custom labeling and packaging — so thermal pads can be tailored to a specific application rather than used as generic sheet stock.
Whether you're developing solar micro-inverters, EV power electronics, or any application where heat source locations and enclosure space keep shifting during development, T-Global's thermal materials offer the flexibility to iterate quickly at any stage. And when your design is ready to move to production, our potting compounds are there to help you seal and protect the finished assembly.