TO-39 Package
The TO-39 package, also referred to as TO-205AD, is a transistor package commonly used for discrete general-purpose transistors. It is a through-hole package with a metal flange for heat dissipation, making it suitable for high-power applications. The TO-39 package is commonly used for housing transistors and integrated circuits with a low number of leads. At EPI, we offer TO-39 packages in various standard and customized designs to retrofit obsolete packages or integrate into new product designs.
These transistor packages, available with up to 8 leads, can be designed and manufactured to retrofit obsolete packages or be used in new product designs. The combination of material options, including plating, housing material, glass, and pins, ensures that EPI can design the exact combination to hermetically seal within your environmental conditions. Further customization is available with weld projections, customized pin circle diameters, and the type and length of pins.
At Electronic Products (EPI), we also offer a variant of the TO-39 in the TO-5 transistor outline package. This is available with up to 14 leads while using less metal than the TO-39 transistor outline package.
Additionally, the TO-39 header is an integral part of the TO-39 package, providing robust support and reliable performance for your applications.
By leveraging these options, EPI ensures that our TO-39 packages meet your specific needs for durability and efficiency.
TO-39 hermetic header with 5+1 configuration
FAQs
What is a TO-39 package?
The TO-39 is a type of transistor package commonly used for discrete general-purpose transistors. It’s a metal can with protruding leads for mounting on a circuit board. The metal construction allows for efficient heat dissipation, which is important for transistors.
What are the similarities and differences between TO-39 and other transistor packages?
- Similarities: Both TO-39 and other packages like TO-220 or TO-92 house transistors. They offer electrical connections through leads. TO-5 packages are the same diameter, but utilize less material overall.
- Differences:
- Material: TO-39 uses metal for heat dissipation, while others like TO-92 are plastic and less efficient with heat.
- Size: TO-39 is larger, making it unsuitable for compact designs. TO-220 offers a good balance of size and heat handling.
- Lead configuration: TO-39 has various lead options (e.g., axial, isolated center lead), while others may have standardized layouts.
Are there any customizations available for TO-39 packages?
Customizations for TO-39 packages are typically limited. Here are some possibilities:
- Lead length: Some manufacturers might offer options for lead length depending on application needs.
- Plating: Gold plating on the metal can might be available for improved corrosion resistance (check with the manufacturer).
Why choose a TO-39 package?
Choose a TO-39 package when:
- You need a transistor that can handle high power and dissipate significant heat.
- The application prioritizes robustness and durability over size constraints.
- Your design already uses TO-39 footprints and requires a compatible replacement.
Are TO-39 packages becoming obsolete?
While less common in modern consumer electronics due to their size, TO-39 packages are still relevant for high-power applications, industrial equipment, and high-end audio devices where heat dissipation is critical.