Feedthrough Connector

Key Takeaways

• A feedthrough connector enables signals and power to pass through a PCB while maintaining electrical isolation between different layers.

• Feedthroughs come in various types, including plated-through holes, feedthrough capacitors, and specialized connectors.

• Feedthrough connectors are vital for applications where signals, power, or other connections must pass through the PCB while preserving specific electrical, environmental, or mechanical conditions.

Noise suppression feedthrough capacitors (a type of feedthrough connector)

A feedthrough connector enables signals and power to pass through a PCB while maintaining electrical isolation. The connector usually consists of a metalized hole or conduit through the PCB, often with insulating materials to prevent electrical contact between the conductive layers. It is commonly used in applications where maintaining signal integrity, minimizing crosstalk, or isolating different portions of a circuit is critical.

Feedthrough connectors come in a variety of types, including plated-through holes, feedthrough capacitors, and specialized connectors. They play a crucial role in ensuring the functionality and performance of complex electronics. The table below presents a quick overview of the purposes and types of feedthrough connectors.

The types mentioned above are general categories, and specific designs may vary based on the application's requirements and the desired characteristics of the feedthrough connectors.

Feedthrough Connector Applications

When signals, power, or other elements must cross from one side of the PCB to the other, feedthrough connectors are used to maintain electrical isolation or specific environmental conditions. Here are some typical applications of feedthrough connectors:

• Power Supply Filtering: Filters and stabilizes power signals between components, such as capacitors or inductors.

• EMI/RFI Shielding: Provides electromagnetic interference (EMI) and radio-frequency interference (RFI) shielding in sensitive electronic circuits.

• Hermetic Sealing: Passes wires or other connections through the PCB while maintaining a sealed environment; for applications where a hermetic seal is necessary, such as implantable medical devices.

• Sensor Connections: Allows the sensor signals to pass through the PCB without compromising the integrity of the sensor's housing or the PCB.

• High-Frequency Signaling: Enables RF signals to pass through the PCB while maintaining controlled impedance and minimizing signal loss.

• Battery Connections: Connects batteries or power sources to the PCB, which enables easy replacement or recharging of batteries without compromising the overall device design.

• Vacuum Systems: Passes signals or power through the PCB while maintaining a vacuum-tight seal; for application in vacuum systems used in scientific and aerospace instruments. 

• Data and Communication: Passes data signals or communication lines through the PCB, especially in applications where feedthroughs need to be mounted directly on the PCB.

In PCBs, feedthrough connectors are vital for applications where signals, power, or other connections must pass through the board while preserving specific electrical, environmental, or mechanical conditions. Many industries rely on these connectors to enhance their electronic systems' functionality, reliability, and performance.

Implications of Feedthroughs for PCB Designs

Using feedthrough connectors in PCB designs introduces several implications for PCB designers. While these connectors offer unique benefits, designers must consider various factors to ensure proper functionality, reliability, and manufacturability. Here are some important considerations for incorporating feedthroughs in PCB design:

• Plan the board placement of feedthroughs to minimize signal crosstalk, ensure proper clearance, and maintain an organized and manufacturable design.

• Ensure the feedthrough’s impedance matches the transmission line to prevent signal reflections and ensure proper signal quality.

• Assess the impact of feedthroughs on power integrity; proper filtering and decoupling capacitors may be necessary to minimize noise and ensure stable power delivery.

• Select feedthroughs with suitable shielding properties and incorporate additional measures to mitigate EMI/RFI.

• Ensure that hermetic sealing requirements are met by carefully considering materials, manufacturing processes, and testing.

• Select materials based on the application's requirements since materials used in feedthroughs can impact their electrical performance, thermal characteristics, and overall reliability. 

• Consider the impact of feedthroughs on manufacturing and assembly; complex designs or challenging assembly processes may increase manufacturing costs and decrease overall reliability.

• Conduct testing and validation procedures to ensure that the feedthroughs meet the specified performance criteria and comply with industry standards.

• Balance performance requirements with cost considerations and choose feedthroughs that offer the best value for the specific application.

While feedthrough connectors provide valuable solutions for certain applications, PCB designers must carefully evaluate and address the implications associated with their use. 

Cadence Has the Tools You Need

Proper planning, material selection, layout considerations, and testing procedures are essential to integrate feedthrough connectors into PCB designs successfully. Cadence has the PCB Design and Analysis Software, including our OrCAD PCB Designer, you need for your PCB design project. 

Leading electronics providers rely on Cadence products to optimize power, space, and energy needs for a wide variety of market applications. To learn more about our innovative solutions, talk to our team of experts or subscribe to our YouTube channel.