Specifying medical device connectors

By Contributed Article | January 19, 2017

Designing handhelds, wearables, and tomorrow’s smaller medical devices comes with a unique set of design challenges. Engineers and designers are striving to drive size, weight, and cost from their devices, looking critically at every component, including medical device connectors.



Handhelds, wearables and more: Smaller medical devices mean smaller, multi-tasking connectors

New technology in connector design is changing how medical device manufacturers build smaller, more reliable devices than ever before. One approach is the increased use of small hybrid connectors that combine signal, power, and data into one small, dense connector.

This is particularly helpful when the patient is responsible for maintaining the device on a daily basis. Patients who are not technologically proficient bring their own set of challenges and risks to the table, especially when their own failing health plays a role. The fewer the connections and cables that have to be managed, the lower the risk of an in-home device problem due to user error.

Suppliers constantly work with engineers designing handheld or wearable connector solutions that take up less space and handle a broader range of functions. The most common is putting power and signal into one connector. But there are other combinations, such as power and fluid or air, specifically in the medical industry that play a role as well. Those engineers report that their end-use customers ask for simplicity and ease-of-use while still maintaining safety, reliability, and FDA-level or appropriate country medical device directive quality standards. It is no small task to satisfy everyone.

Moving from the older, larger connectors that handle only signal or only power to smaller connectors that handle both power and signal comes with a bit of a learning curve. The problem is that most engineers don’t get the chance to review their connector solutions all that often, especially when they need to pass FDA trials. However, reviewing the connector and cable assembly needs and possibilities early in a project can save a lot of heartache later on.

If the connector solution is typically connected and then forgotten, those working on new designs have myriad solutions available. They can minimize the number of wires coming out of the connector to make sure medical professionals or patients can easily handle the single connection. In some instances, they don’t need to worry a lot about how the connectors feel, or whether they are easy to connect and disconnect over a period of time. When connectors aren’t touched very often, it’s important to make sure the signal and power connections don’t create interference and are as small as possible.

But if the connector solution is mated and unmated often, the end user and the environment must be closely examined. For instance, a solution in a hospital surgical environment where staff is wearing gloves will have different needs than connectors for a patient in poor health who can’t grasp small connectors.

Here are a few tips to consider when going to a hybrid connector solution that multi-tasks in a frequent-use application.

  • Sure, it’s easy to determine the contact count. But details become more important as the voltage and current increases. Compare models for the exact size of the contact. A 0.5mm contact will carry more power than a 0.3mm contact. The smaller the contact, the lower the current it will pass. Early connector failures can occur if too much power is run through a small contact.
  • Pin density and configuration are important. The ideal connector performs several functions including transmission of power, Ethernet, HDMI, etc., without interference. The cable plays a significant role, but connectors without the proper spacing may play havoc with data transmission if there are unexpected levels of interference. Combinations of data, signal and power need to be tested as no two applications are exactly the same.
  • Check for available keying and color-coding variations so that users can quickly and easily determine where to connect a specific cable.

Review for overall ruggedness:

  • Make sure to get enough mating cycles out of the connectors. If 5,000 mating cycles are needed, make sure the connector solution can handle them. Determine how many mating cycles per day are expected and the probable product lifetime to come up with a target for the minimum required mating cycles.
  • Check to make sure that connector can be sealed to product requirements. Not every IP68 solution is created equally. IP68 can be achieved with a test of one meter for two hours or 120 meters for 24 hours. There’s a big difference, so take the time to understand what’s behind every provider’s IP68 testing. On the other hand, don’t pay for sealing levels that aren’t needed.
  • When sterilization is an issue, be sure to understand which sterilization method will be used. Different methods need connectors with different materials.

Cable configurations:

  • Be sure that the cable selected works best for the application. Not every cable with multiple twisted pairs is the same. If a specific data speed is required, be sure to specify it.
  • With today’s smaller connectors, be sure that the cable and connector actually mate. People often ask for cables that are too big for the connectors.

Working with hybrid connectors doesn’t end with traditional copper connectors. Many companies offer fiber-copper hybrid connectors and cables to move a lot of data a long way and provide power.

So what is the payoff? Customers have been able to make substantial changes to designs by making hybrid connectors part of their solution. Replacing two connectors with one lowers the total cost of ownership. It simplifies design, and makes the systems more efficient, and maybe – just maybe – makes everyone a little happier.


Earl Kneessi is a Sales Engineering Manager at Fischer Connectors.

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