R2A-CT4-38E
Heat Sink, 8.6 °C/W, TO-247, 35.2 mm, 38 mm, 22 mm
- Manufacturer: OHMITE
- Product type: Natural Convection Heat Sinks
- SVHC: No SVHC (27-Jun-2024)
- Product Range: R2 Series
- Packages Cooled: TO-247
- Heat Sink Material: Aluminium Alloy
- Thermal Resistance: 8.6°C/W
- External Width - Metric: 35.2mm
- External Height - Metric: 38mm
- External Length - Metric: 22mm
- External Width - Imperial: 1.38"
- External Diameter - Metric: -
- External Height - Imperial: 1.5"
- External Length - Imperial: 0.87"
- External Diameter - Imperial: -
| Delivery and price | |
|---|---|
| Units per pack | 5 |
| Price | 3.0 € |
| Current stock | 10+ |
| Lead time | 30 days |
## **R2 Series For TO-247 and TO-264** ## **F E A T U R E S** - **Reduced Assembly Cost:** C Series camming clips make fasteners and fixtures obsolete, along with stray metal filings from tapped holes. - **Maximum Repeatability:** clamping force of the clip is not degraded by repeated loading and unloading. - **Maximum Heat Transfer per Unit Space:** maximum surface area per unit volume and consistent mounting force reduces thermal resistance Ohmite’s R2 Series (patent pending) heatsink provides a large surface area along with our C Series clipping mechanism to attach to a TO-247 or TO-264 package. The self-aligning features of the clip assure secure attachment and enhanced thermal performance. Because no screws are required for device mounting, additional fins can be added to the rear side of the heatsink for increased total surface area in a more compact space. - **Maximum Resistance to Shock and Vibration:** light weight, resilient clips lock the component in place and are highly resistant to shock and vibration - **Maximum Reliability:** helps prevent short circuits by eliminating metal particles from thread tapping - **RoHS compliant** |~~**S E R I E S S P E C I F I C AT I O N S**~~<br>~~ee~~|~~**S E R I E S S P E C I F I C AT I O N S**~~<br>~~ee~~|~~**S E R I E S S P E C I F I C AT I O N S**~~<br>~~ee~~|~~**S E R I E S S P E C I F I C AT I O N S**~~<br>~~ee~~| |---|---|---|---| ||**Surface**||**Thermal**| |**Heatsink**|**Area**|**Weight**|**Resistance***| |**Part Number**|**(in2/mm2)**|**(oz/g)**|**(°C/W)**| |R2V-CT2-38E|21 / 13,579|0.92 / 26|9.8| |R2A-CT2-38E<br>21 / 13,579<br>0.92 / 26<br>8.6<br>~~Oe~~|||| |R2V-CT4-38E|21 / 13,579|1.02 / 29|9.8| |R2A-CT4-38E|21 / 13,579|1.02 / 29|8.6| |R2V -CT6-38E|21 / 13,579|1.02 / 29|9.8| |R2A-CT6-38E|21 / 13,579|1.02 / 29|8.6| |*Free convection at 15W<br> = Discontinued<br>~~n°Sr~~|||| ~~ee~~ ~~**C H A R A C T E R I S T I C S**~~ **Heat Sink**[Aluminum Alloy 6063-T5 or Equivalent with either degreased or black anodized ] finish **Spring Clip**[Music Wire, Per ASTM A228 with bright nickel plating] |**Solder Foot**|Cold-rolled Steel, Per ASTM A-366 with pure tin over copper strike. RoHS compli-| |---|---| ||ant| |**Interface Thermal Resistance**|for improvement, use thermal joint compound, 0.005 Grafoil (TGon 800 by Laird),| ||orphase change material(Hi-Flow byBergquist)| |**Insulato**r|(Optional) Sil-Pad 900-S, K6 800-S and K10| (continued) **178** 1-866-9-OHMITE • Int’l 1-847-258-0300 • Fax 1-847-574-7522 • www.ohmite.com • info@ohmite.com ## **R2 Series** ## **For TO-247 and TO-264** ## ~~**H E AT D I S S I P AT I O N**~~ **==> picture [292 x 461] intentionally omitted <==** **----- Start of picture text -----**<br> Air Velocity (ft./min.)<br>0 100 200 300 400 500 600 700 800 900 1000<br>160 3.5<br>140 3<br>120<br>2.5<br>100<br>2<br>80<br>1.5<br>60<br>1<br>40<br>20 0.5<br>0 0<br>0 2 4 6 8 10 12 14 16 18 20<br>Heat Dissipated (watts)<br>D I M E N S I O N S<br>CT4 & CT6: 0.69" ±.01 (17.6mm)<br>CT2: 0.47" ±.01 (11.9mm)<br>2x ø0.08" ±.01<br>(2.0mm)<br>0 .18" ±.01<br>(4.6mm)<br>0.39" ±.01<br>(10.0mm)<br>Holes on PCB<br>0.80" ±.01 ø0.05" typ.<br>(1.3mm)<br>(20.3mm)<br>0.87" ±.01<br>1.38" ±.02<br>(22.0mm)<br>(35.2mm)<br>1.5" ±.02<br>(38.0mm)<br>1.44" ±.02<br>CT2: 0.55" ±.02 (36.5mm)<br>(14mm)<br>CT4 & CT6:<br>0.71" ±.02 (18mm)<br>0.14" ±.025 CT4 & CT6: 0.69" ±.02 (17.6mm) Solder lead protrusion over PCB<br>(3.6mm) CT2: 0.47" ±.02 (11.9mm) meets class 2 or 3 of IPC 610 STD<br>Thermal Resistance<br>Case Temp Rise Above Ambient in Free Air (°C) Case to Ambient (°C/W)<br>**----- End of picture text -----**<br> TO-247 with no thermal interface material ## ~~**H O W T O O R D E R**~~ **Series Clip RoHS** R2 C = camming clip **Compliant R 2 V - C T 4 - 3 8 E Finish Package Height** A = black anodized T4 = TO247 (mm) V = degreased T6 = TO264 _T2 = TO220 (discontinued)_ ## **R 2 V - C T 4 - 3 8 E** rev 7/22-2 1-866-9-OHMITE • Int’l 1-847-258-0300 • Fax 1-847-574-7522 • www.ohmite.com • info@ohmite.com **179**
Updated at April 29, 2026
With nearly a century of engineering expertise, Ohmite is a premier manufacturer of high-performance resistive and thermal management products. Founded in 1925, the company has continuously evolved alongside the electronics industry, building a reputation for resolving complex design challenges. Ohmite specializes in delivering reliable solutions for high-current, high-voltage, and high-energy applications across the industrial, medical, aerospace, and transportation sectors. The core of our Ohmite offering centers on their advanced cooling and thermal management solutions, particularly natural convection heat sinks. Engineered to efficiently dissipate thermal energy in demanding environments, these heat sinks help designers overcome critical thermal bottlenecks. By effectively managing heat dissipation, Ohmite's thermal products ensure the optimal performance and extended longevity of sensitive electronic assemblies. Complementing their thermal management expertise, our selection includes precision sensing and circuit protection components. Ohmite's robust force sensors and load cells provide dependable measurement capabilities for specialized industrial applications, while their temperature sensing and compensation NTC thermistors offer accurate environmental monitoring. These product lines reflect Ohmite’s enduring commitment to quality, innovation, and specialized component engineering.
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