In the world of microelectronics, choosing the right packaging solution directly impacts the performance, reliability, and longevity of your components. One common comparison is TO-39 vs TO-46, two of the most transistor outline (TO) packages. Both are recognized for their hermetic sealing, dependable metal can construction, and JEDEC-standard configurations, yet they serve different roles in the electronics ecosystem.
What are TO-39 and TO-46 Packages?
TO-39 hermetic package
TO-39 Package:
TO-39 is a mid-sized TO header with a metallic body and hermetic sealing. Known for its excellent thermal conductivity and strength, it supports up to 8 pins, with multiple ISO and Ground positions. It’s a favorite in power transistors, RF devices, and high-reliability sensors.
The larger body allows for improved thermal performance, making it suitable for heat-intensive applications. TO-39 headers are also available with customizable lead configurations and plating options to meet specific design and assembly needs.
TO-46 hermetic package
TO-46 Package:
TO-46 is a smaller, space-efficient TO package ideal for compact applications. It supports up to 4 pins and is frequently used in photodiodes, laser diodes, optoelectronic components, and other high-frequency systems. Its reduced footprint makes it an excellent choice for densely packed circuit boards and miniaturized devices.
Despite its size, it maintains excellent signal integrity and hermetic sealing for long-term reliability. TO-46 packages are also available with different plating finishes and venting options to suit specific performance and assembly requirements.
EPI’s TO Header Capabilities
Understanding the physical differences between TO-39 vs TO-46 packages is key to selecting the right one. Here’s a quick comparison of their dimensions:
| Feature | TO-39 | TO-46 |
|---|---|---|
| Max Pin Count | 8 | 5 |
| Max ISO Positions | 8 (flexible placement) | 4 |
| Max Ground Pins | 3 | 3 |
| Pin Circle Diameter (PCD) | 0.2″ | 0.1″ |
| Lead Styles | Straight-Cut, Nailhead, Upset | Straight-Cut, Nailhead, Upset |
| Body Diameter | 0.360″ | 0.210″ |
| Body Material | Kovar, Steel | Kovar, Alloy 42, Steel |
| Tab Option | Yes/No | Yes/No |
| Plating Options | 100–350 µ” Nickel + 3–150 µin Gold | 100–350 µ” Nickel + 3–150 µin Gold |
| Lead Length | 0.05–1.5″, 0.50” Standard | 0.05–1.5″, 0.50” Standard |
Both packages are constructed from high-reliability materials like Kovar, Cold Rolled Steel (CRS), and Alloy 52, and plated using gold over nickel, ensuring optimal conductivity and long-term performance.
Key Differences between TO 39 Package and TO 46 Package
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- Size and Design Differences:
TO-39 offers greater surface area for larger devices. The weld ring on the TO-39 has the option of having a weld projection to enhance the welding performance of the cap. TO-46 is ideal for miniaturized and signal-sensitive systems like photodiodes and sensors. - Thermal Performance and Heat Dissipation:
Heat management can be enhanced slightly with CRS vs Kovar. Typically the power requirements on TO headers is low. - Electrical Performance and Reliability:
Both packages offer reliable electrical performance, but TO-46 is often preferred in high-frequency and signal-sensitive applications due to its compact design, which minimizes inductance and improves signal integrity. - Design Flexibility and Customization:
At EPI, both packages are available with custom pin configurations, venting options, weld projection options, and various plating finishes. The TO-39 provides more flexibility in pin layout due to its size, while TO-46 is advantageous in applications that require tighter mechanical tolerances.
- Size and Design Differences:
Application-Specific Considerations:
- TO-39 Applications: You’ll find TO-39 packages in power transistors, RF devices, and high-power sensors where thermal management is a priority.
- TO-46 Applications: TO-46 shines in miniaturized sensors, photodiodes, and high-frequency applications where space-saving is critical.
- Material and Construction Differences: Both TO-39 and TO-46 feature metallic bodies that provide durability and environmental protection. TO-39 packages are often made of kovar or similar materials, offering robustness against thermal expansion. TO-46 shares similar construction but focuses on a smaller footprint and reduced weight, making it suitable for delicate, compact devices.
Pros and Cons of TO-39 and TO-46 Packages
TO-39 Pros and Cons:
- Pros: Enhanced heat dissipation, robust construction, and ideal for high-power applications.
- Cons: Larger size, which may not fit compact designs.
TO-46 Pros and Cons:
- Pros: Compact size, efficient for high-frequency operations, and excellent for miniaturized designs.
- Cons: Limited heat dissipation compared to TO-39, making it less suitable for high-power scenarios.
Choosing the Right Package for Your Application
When deciding between TO-39 vs. TO-46 options it’s important to take into account the requirements of the application. TO-39 is ideal, for high power devices that require management. On the hand TO46 is preferred for high frequency applications that prioritize saving space. Consider aspects such, as operating conditions, thermal needs and electrical capabilities when making your decision.
At EPI, we provide a range of customization choices for TO-39 and TO-46 packages including lead counts and configurations as well as advanced glass, to metal seals. Our packages are tailored to meet your requirements with our knowledge and experience guaranteeing you notch and dependable TO packages that adhere to industry regulations.
Why Choose EPI for TO Headers?
At Electronic Products Inc. (EPI), we specializes in producing TO packages and headers tailored to meet the stringent demands of modern microelectronic systems, with hybrid integration options, vented configurations and customized mechanical layouts that meet our highest standards of production.
JEDEC Compliance:
Our TO headers and packages meet JEDEC standards to guarantee global interoperability, mechanical consistency, dimensional consistency, as well as compliance to industry-defined dimensional and material standards for reliable long-term performance. This ensures smooth integration into existing systems while ensuring reliable long-term performance.
Our Capabilities:
- TO packages and headers engineered specifically to comply with JEDEC standards.
- Custom PCDs (Pin Circle Diameters) for exact component fitment.
- Weld projection stamping and cap compatibility.
- Hybrid TO packages with heat spreaders, ceramic insulators and thermal vias.
- Hand-wiring or automated assembly are suitable for low to high volume production runs.
- On-site electro-less and electrolytic plating for enhanced conductivity and durability.
Whether you’re building pressure sensors, thermal imagers, or RF switches, EPI can deliver TO packages and TO headers that perform under harsh environment and pressure.
Conclusion: Which TO Header is Right for You?
TO-39 packages and TO-46 packages each bring unique advantages to the table. Whether you need superior heat dissipation or a compact design for space-constrained applications, understanding their differences helps you make an informed decision. Explore EPI’s range of TO packages to find the right fit for your electronic components.
Contact us today to discuss your requirements and explore customized solutions with our experts.
