Jeff Gaumer / Product Manager / Molex
The effectiveness and reliability of healthcare devices and systems rely on the robust design, engineering and performance of their underlying electronics. As medical equipment manufacturers work to reduce device cost, without sacrificing reliability, connector choice is one of many decisions that require striking a balance. A wide range of connector options make the choice more challenging.
For instance, a custom or hybrid connector may be appropriate in particular applications, but these would typically require higher upfront engineering, tooling fabrication time and expense. Fully customized designs are somewhat costly, but allow for almost any required specification. A hybrid connector, on the other hand, is essentially an off-the-shelf connector with custom features, such as an overmolded grip or strain relief. Design and tooling costs are lower, and a hybrid has the look and feel of a custom connector. However, when developing a list of power connector requirements, design engineers should not rule out viable and more economical off-the-shelf connectors.
Of course, there are a few things to consider when selecting or specifying a connector. For example, the connector’s mechanical interface, including the friction between each pin and socket, determines mating force and its important role in how a medical device performs in the real world. Some overly tight, off-the-shelf connectors are a risk in medical care environments. Conversely, loose or unstable connections in some devices are also a risk in healthcare environments.
Moisture creates another set of problems. Medical device I/O connectors may be susceptible to the ingress of moisture and other contaminants. A solution would be to pot the connector-contact interface for both plug and receptacle, to prevent ingress of flux into the contact zone during soldering, as well as to prevent ingress through the pin field during use in a hospital or clinical setting. Because moisture protection is a consideration in medical connectors, an additional IP64-rated sealing option should be available to provide protection to a splash-proof specification.
As a solution, Molex offers a “semi-customized,” off-the-shelf power connector. MediSpec Medical Plastic Circular (MPC) connectors and cable assemblies meet stringent industry standards and provide exceptional performance at a fraction of the cost of machined-contact systems and custom circular connectors. The MPC connector system has a 10,000-cycle durability rating, which makes it ideal for I/O applications in medical imaging equipment, patient monitoring, surgical equipment and devices, and telehealth remote patient monitoring systems.
MediSpec MPC connectors balance the need for high mating cycles and low mating forces. Employing the proven low-force helix and stamped-and-formed contact design, the MPC connectors ensure a reliable electrical interface over multiple insertions. The simple, push-pull engagement mechanism provides easy handling, even when wearing surgical gloves.
MediSpec MPC cable assemblies provide between 15 and 20N unmating force. An optional locking sleeve can ensure the cables will remain mated to a force that complies with ANSI/AAMI-EC53 specification (greater than 90N) to prevent accidental un-matings.
Fully functional and tested generic pig-tail harnesses will also be offered to facilitate early system R&D and design activity. These will provide a quick and easy means to build early prototypes of new medical devices.
A checklist of specs for a medical connector
We suggest specifying these features before selecting a connector for a medical device. Identify the:
- Number and type of contacts (pins or sockets and specifications for each)
- Cable configuration (power, ECG, defibrillator, analog, digital bandwidth, pneumatic, fiber optic or combination of two or more)
- Cable diameter, materials and shape
- Regulatory and environmental ratings (RoHS, REACH, ISO 10993 and UL)
- Strain relief requirements
- Shielding requirements for connector and cable
- Voltage and current requirements
- Space and size constraints, a preferred connector diameter
- Ingress protection (IP) rating
- Number of mate and un-mate cycles required
- Locking mechanism, when required
- Keying requirements
- Required mate and un-mate force
- Cleaning, disinfection and sterilization requirements
- Color, logos, markings and serialization