Interconnect Connectors: A Brief, Technical Overview
If you’ve read our guide about interconnect solutions, you know that developing the right interconnect for your device can be a challenging task.
It requires an understanding of interconnect drawings, schematics, capacitance, resistance, delay, and much more.
On top of that, you must also understand the components that make up the interconnect solution and enable it to function.
In this post, we’re going to be talking about one of the most important parts of any interconnect solution: the interconnect connector.
What are interconnect connectors?
An “interconnect connector” is any part or component within an interconnect solution that enables it to connect with another part or component.
In other words, “interconnect connector” is a more technical way of saying “connector.”
So, from this point forward, we’ll use “interconnect connector” and “connector” interchangeably.
An interconnect solution may utilize one or many connectors to function properly.
How many a given device requires depends on the application and design of the device itself.
What are the components of an interconnect connector?
Though not every connector will contain every component listed below, there are two basic components that make up a connector: contacts and housings.
Contacts (sometimes referred to as current carrying pins, sockets, blades, spring-pins, etc) are the components of the connector that actually enable the electrical connection to work.
When talking about connectors, contacts are often categorized as either male or female.
Male “pin” contacts are typically identified as solid, protruding pieces of metal—like the “prongs” on a computer’s power cord.
Female “socket” contacts typically appear as encapsulated pieces of metal that fit around the male pins—like the “holes” in the wall outlet.
When the male and female contacts of an interconnect connector engage each other, they enable the transfer of electricity and/or data from one product to another.
Contacts are usually connected to a wire using soldering, crimping, or insulation displacement.
As the name implies, solder contacts are designed to have the wires soldered directly to the contacts.
With the proper equipment and skillset, soldering can be an efficient method for creating a strong connection.
Crimp contacts consist of a wire inserted into a hole or other aperture in the contact.
Once inserted, the wire interface region of the contact is squeezed (“deformed”) tightly against the wire.
This method makes for quick connections, though good process controls are required to assure proper crimp quality.
Insulation displacement contact (“IDC”) technology removes the need for wire stripping and allows for the rapid connection of multiple conductors.
Within an IDC connector, the contact contains a slot with sharp edges that is sized to securely interface with wire conductor.
Wires are pressed into the slot and the edges of the slot cut through the insulation as the wire is forced to the distal end of the slot—completing the connection.
There are three primary types of male/female contact mating solutions: pin and socket, blade and beam, and pogo pin and pad.
Pin and Socket
When people think of “connectors” this is the image that most likely comes to mind.
As the name implies, a pin and socket mating solution consists of male “pins” that establish a connection by making contact with female sockets (e.g., a computer cable prongs connecting with the wall outlet).
In general, pins and sockets are manufactured by either machining or stamping.
Machined solutions are typically high quality, high cost, and intended for a long life, while stamped solutions are of reasonable quality and cost, but intended for shorter-life applications
Blade and Beam
Similar to an ethernet cable, a blade and beam mating solution typically consists of a flat, stamped “blade” for the fixed (i.e., male) contact and a simple, flexible stamped beam for the compliant contact.
When designed and manufactured correctly, these contacts offer good performance relative to their price point as tooling is extremely simple and automation is easier and more cost effective to implement.
Pogo Pin and Pad
A pogo pin and pad solution consists of a spring-loaded pin that is pressed and held against a flat mating pad.
This type of solution is common in magnetic charging cables for consumer products.
Unlike the other two mating solutions, a pogo pin and pad requires a separate mechanism to hold against the separating force created by the pogo pin spring.
Another consideration with this type of mating solution is that contact integrity can be compromised due to lack of wiping action during mating (wiping cleans the surfaces).
Ethernet Cable with Blade and Beam Contacts
“Housing” refers to the pieces of the connector that separate and space the contacts.
In general, housings are categorized as either the “plug” or the “receptacle.”
The plug is the part of the connector that typically houses the male contacts.
Without the plug, the end of a cable would look like a collection of loose wires.
This would be non-ideal because the various contacts may come into unwanted contact with each other, which can cause performance and safety problems.
The plug makes it easier to connect two separate interconnects as it offers people something to safely grip and should be designed to act as a guide for orienting the connector so that the correct male pins align with the correct female sockets.
The receptacle is the part of the connector that typically houses the female contacts.
Put another way, the receptacle is the component that the other half of the connector plugs into.
Though the receptacle is technically a housing (as it houses the female sockets), it is commonly referred to as a separate component.
A wall outlet is an example of a commonly found receptacle.
What are interconnect cable connectors?
When most people think of the words “interconnect connectors,” this is the typical type of connector that comes to mind.
An interconnect cable connector is any connector that is attached to the end of an electrical cable with the purpose of terminating the wires within the cable and enabling the cable to connect with another product.
An example of a cable connector would be the plug on the end of a computer cord or the USB fitting that connects your phone charging cable to the outlet.
In the medical device realm, cable connectors can be found attached to the cable of any energy-driven device that must be plugged into a computer or piece of capital equipment in order to function.
What are PCB interconnect connectors?
Due to their electrical capability and relative affordability, printed circuit boards (“PCB”) can be found in electronics we use daily—from our computers to our TV remotes.
PCBs are typically categorized as rigid, semi-rigid, or flexible (a flex PCB is also sometimes referred to as a “flexible interconnect”).
Within the medical device world, PCBs can be found in the hand-pieces, cannulas, and capital equipment of many of the energy-driven minimally invasive and electrophysiology devices on the market.
In fact, our proprietary Chip-on-Tip® technology utilizes a complex flex PCB to function.
Though they may not seem as commonplace as cable connectors, PCB interconnect connectors are used quite frequently to connect PCBs to cables, components, and even other PCBs.
In general, PCB connectors can be defined as any part or component that attaches to a PCB and enables the transfer of power or data to another part or component.
Custom Interconnect Connectors vs Off-the-Shelf Connectors
During any given energy-driven medical device development project, one of the questions that inevitably arises is: Should I develop a custom connector or use an off-the-shelf connector?
The answer is: it depends.
Unfortunately, there is no universal, one-size-fits-all answer to this question.
Factors such as the application of the device, the forecasted device volume, the development timeline, and the target device and project cost all impact the decision to use a custom connector or an off-the-shelf connector.
If you’re developing a cutting-edge device that has stringent requirements, high-volume demands, and must fit a non-standard port on a piece of capital equipment, you will probably be in a better position with a custom connector.
If you’re developing a simple cable assembly for low-volume production that will utilize standard equipment and connection points, an off-the-shelf connector may be a better bet.
We’ve tried our best to explain the typical situation in which it’s better to use a custom connector over an off-the-shelf connector—and vice versa—in our eBook, Settling the Custom vs Standard Connector Debate Once-and-for-All.
Connectors play a crucial role in any interconnect solution.
In keeping with Bushnell’s Law, learning about connectors and establishing a baseline understanding of what they do is relatively straightforward.
Getting to the point where you can identify exactly which type of connector will work with a given PCB, cable, or piece of equipment can be a challenging road.
For this reason, we recommend speaking with an interconnect expert who can help you find or develop the perfect connector for your next device project.
To further develop an understanding of interconnect solutions, download our ultimate guide: