The ABCs of Connectors

We wanted to dedicate this next couple of weeks’ posts to discuss connectors/interconnect solutions, starting with the basics and working to share some of the innovations in the field of connectors, including what a medical device engineer should look for when selecting a connector supplier. Hope you enjoy!

It’s not too far-fetched to assume that this morning you woke up, got ready for your day and grabbed at least one mobile device before scurrying out the door. Imagine that as you jumped in your car or sat down on the train, to your astonishment, your device had failed to charge—despite being plugged in—due to a faulty power connection. That simple connection we think so little about has created a completely unnecessary headache.

On a daily basis, we take these connections—and so many more of equal and even greater importance— for granted, and don’t think about how critical these connection are until there’s a disconnect.

One industry where connectors or interconnect solutions have become increasingly significant is in the medical world. Devices that have historically been non-electric are evolving, advancing and connecting to power and data, the critical nature of these connections are such that they, literally, can be the difference between life and death. As the evolution and complexity of the medical device moves forward, the connector cannot be seen as an “off-the-shelf” component any longer.


So, what is a connector?

'Connector' is such a broad term. We use connectors every day when we charge our smartphone, tablet, laptop, or plug in our TV, coffee maker or hairdryer. But what should an engineer think of when discussing a connector or interconnect solution?

According to John Holloway, Primary Engineer at ATL Technology, “to start, you need to ask a few basic questions:

  • “How many times does it need to connect?
  • “How long will it be used once it connects?
  • “What contacts will we be using?
  • “How many conductors do we need?“


No one-size-fits-all connector solution

There are thousands of possible solutions to connect your devices. Whether you operate in a medical setting, in the tech sector or just plan to stay connected at home, there are three basic categories for connectors or interconnect solutions:

  • One Time Use (OTU)
  • High Cycle Life (HCL)
  • Permanent Installation (Connect it, Leave it Alone)


One-Time Use

Largely used within the medical industry to eliminate contamination, one-time use connectors are designed to be mated once and used for a procedure such as:

Even though OTU connectors are designated for single use, in practicality, they need to withstand at least 30 cycles with no degradation in performance. This makes it possible for testing at OEMs like ATL—as well as for end users—to connect and reconnect multiple times (to detangle cables or verify full insertion).

Low cost is a typical requirement of an OTU connector, and attributes are typically thin plating, with inexpensive alloys and plastics since fatigue is not a concern.


High Cycle Life

Similar to the use and abuse your mobile device’s power cord receives, high cycle life connectors are frequently mated and detached during a use. Some of the common connectors are:

  • USB, HDMI, small appliance power cords, docking bays, etc..
  • Applications are products like reusable instruments, portable device charging and data connections (think cell phones) and a host of others.

Typical attributes for HCL connectors are more costly contacts (Phosphor Bronze and Beryllium Copper) and heavier plating to support constant usage.


Permanent Installation

Permanent installation connectors are typically connected once and then left alone until service or repair of a device is needed.

Examples of permanent connections are automotive applications, internal equipment connections PCB edge connectors, etc.

Challenges can be wearing from vibration, fretting corrosion, and durability of plastics and seal materials, particularly in harsh environments.

A few of the typical attributes of permanent connectors are higher contact force, fatigue and creep resistant materials, higher-grade plastic materials and plating selections appropriate for the environment.