Würth Elektronik has expanded its thermal management range with a modular heat sink portfolio for power semiconductors in TO packages and ICs with flat surfaces.
The new WE-HTO, WE-HTOI, WE-HIC and WE-HICI series target design engineers who need predictable thermal performance, defined airflow behavior and simplified assembly when cooling power devices and DC/DC converters.
Key features and benefits
Würth Elektronik now offers a coordinated family of aluminum heat sinks covering common through-hole TO packages and a wide range of IC footprints. The portfolio is structured into three main groups that share a common focus on low thermal resistance and practical handling in real designs.
- WE-HTO heat sinks are designed for THT-TO packages such as TO-220 and TO-247, using curved sheet metal or fins to increase surface area for better heat dissipation.
- WE-HTOI variants are factory-coated with thermal interface material (TIM), eliminating the air gap between package and heat sink and improving thermal coupling without additional assembly steps.
- WE-HIC covers classic finned heat sinks for flat components like CPUs, DC/DC converters and power ICs, in sizes from 20 × 20 to 40 × 40 mm according to the manufacturer datasheet.
- WE-HICI versions add an integrated thermal interface layer on the IC heat sinks for faster and more repeatable mounting in series production.
- All series use aluminum with a black anodized surface for high emissivity and robust mechanical behavior in typical industrial environments.
From a design-in perspective, the pre-coated variants help avoid variability in thermal contact quality due to inconsistent application of pastes or pads. In compact power designs, this can translate directly into lower junction temperatures at a given load, or extra thermal margin for lifetime and derating.
Typical applications
The portfolio is aimed at a broad range of power electronics and embedded systems where discrete semiconductors or power ICs must dissipate several watts or more into ambient air.
- Through-hole power stages using TO‑220 or TO‑247 devices, for example in offline power supplies, motor drives, industrial controllers and PFC stages.
- DC/DC converter modules and POL regulators with flat top surfaces, where local hot spots must be managed without forced liquid cooling.
- Embedded CPUs, FPGAs and ASICs on industrial control boards that require compact board-level cooling.
- Gate driver ICs, power management ICs and other mixed-signal devices that combine logic and power stages on a single package.
- Prototypes and evaluation boards, where the availability of catalog heat sinks and free samples simplifies early thermal validation.
Because the catalog parts are available from stock without minimum order quantity, they can be used both for rapid prototyping and for ramp-up into volume production, with the option of customer-specific modifications if standard sizes do not fully match the mechanical constraints.
Technical highlights
The new heat sinks are part of Würth Elektronik’s thermal management portfolio and are documented with characteristic curves and detailed performance data according to the manufacturer.
- Material and surface: Aluminum construction with black anodized surface for increased surface emissivity and improved radiative heat transfer.
- Form factor for TO packages (WE-HTO / WE-HTOI): Variants with curved sheet metal and fin structures that increase effective surface area for convection, optimized around common TO-220 and TO-247 mounting geometries.
- Form factor for ICs (WE-HIC / WE-HICI): Finned blocks for IC packages with flat top surfaces; available footprints from 20 × 20 mm up to 40 × 40 mm according to the manufacturer datasheet, with different fin geometries for defined versus diffuse airflow.
- Airflow-optimized designs:
- Continuous fins for applications where airflow direction is known and aligned with the fins, supporting efficient channel flow.
- Interrupted fins for environments with diffuse or poorly defined airflow, encouraging turbulence that improves heat transfer even without a clear flow channel.
- Thermal interface options:
- Bare versions for use with user-selected thermal pads, pastes or phase-change materials.
- Factory pre-coated versions (WE-HTOI, WE-HICI) that include an integrated thermal interface layer, simplifying assembly and ensuring consistent thermal contact.
- Accessory hardware: Matching M3 screws, nuts and insulating sleeves can be ordered for mechanical mounting and electrical isolation of TO packages as required.
In practice, choosing between continuous and interrupted fins lets engineers adapt the same footprint to either forced or natural convection conditions. When airflow is guided by ducts or fans, continuous fins tend to minimize pressure drop and maximize linear heat transfer, while interrupted fins become attractive in more open, compact assemblies where airflow cannot be predicted precisely.
Design-in notes for engineers
When selecting a heat sink from this portfolio, engineers should treat thermal design as an integral part of the system architecture rather than an afterthought.
- Start from allowable junction temperature and estimated power dissipation of the component, then derive the required overall thermal resistance from junction to ambient, taking into account junction-to-case and case-to-sink contributions from the manufacturer datasheets.
- Use the characteristic curves provided by Würth Elektronik to map thermal resistance versus airflow and mounting conditions for each heat sink series, then verify that the chosen device meets temperature rise targets under worst-case ambient and load.
- For defined airflow (for example, near a fan or along a channel), prioritize WE-HIC variants with continuous fins; for more diffuse airflow in dense boards or enclosures, consider interrupted-fin versions to promote local turbulence.
- If assembly throughput, repeatability and long-term stability of the interface are important, pre-coated WE-HTOI or WE-HICI parts can reduce process variation compared to manual application of thermal pastes.
- Pay attention to electrical isolation between the semiconductor tab and the heat sink when required by safety standards or system grounding concepts; use the dedicated insulating sleeves and appropriate mounting hardware.
- In compact power stages where EMC and thermal performance interact, coordinate the placement of heat sinks with EMI filters and shielding elements so that airflow is not blocked and hot components do not radiate directly into sensitive nodes.
As with other thermal management solutions, it is recommended to validate the chosen heat sink by measurement under realistic operating conditions, ideally using thermocouples or IR imaging to confirm junction temperature margin and airflow assumptions.
Source
This article is based on information provided by the Würth Elektronik press release on the introduction of its heat sink portfolio, complemented with data and series descriptions from the official Würth Elektronik product pages.