CONNECTORS
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Circular connectors are available from Omnetics Connector Corp. in a range of pin configurations.
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Like many components of medical products, connectors must pack greater functionality into a smaller package. Size reduction is a mantra, of course. Simultaneously, medical equipment designers are continually coming up with special needs that must be met. In terms of connectors, that might mean engineering a special pin array, a unique housing that will integrate the connector and a miniature chip array for a cochlear implant, for example, or providing shielding that will minimize EMI interference.
Pinning down a design
Omnetics Connector Corp. (Minneapolis, MN, USA) puts its focus almost exclusively on micro and nano connectors. The company offers a wide array of standard products, which are often used by design engineers for prototyping, according to director of technology Bob Stanton. Designers will often buy several types of standard miniature connectors and use them for breadboarding or prototyping a new medical device or instrument. After the final design has been tested and debugged, the designer will come back and tell Omnetics what he or she wants changed. For example, the designer may have used a 7-pin connector, but a 5-pin configuration might work better. In designing a prototype of an instrument, a lot of that comes to light during the development process. It can't be accurately predicted at the outset.
"A company that was developing a special design for a neurological probe purchased a connector from our Web site and came back and told us it was working perfectly…after they did some in-house modifications," says Stanton. "It turned out the connector had to be smaller—they basically sawed it in half—plus it only needed three pins.
We took what they had done and designed exactly what they needed for the production-level product," he says.
Almost all customisation today is done over the Internet. "We have a solid modeling team and our customers can work with us online wherever they may be based worldwide," Stanton says. "The computer does all mathematical conversions automatically if different specification languages are used for any reason."
Cutting through the noise
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Cylindrical push-pull connectors from ODU are available in metal, autoclavable plastic, and single-use versions.
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EMI or crosstalk can be a big problem in clinics, hospitals, or even laboratories where various electronic devices are being used. In the surgical arena, signals are racing up and down the cables of surgical instruments as well as peripheral monitoring equipment. Connectors with special shielding have been developed to minimize interference. Refining technologies to prevent crosstalk continues to be a goal of connectors designers.
In this regard, Omnetics has introduced its nano Bi-Lobe with EMI back shell and shielding. The company claims it is the smallest and lightest weighing shielded nano-connector in the industry. Available in wire-to-wire and surface-mount configurations, the Bi-Lobe is designed to provide 85 dB isolation from noise in the circuits.
"It’s not standard shielding," Stanton says. "We offer very flexible and limp shielding specifically for applications in the surgical and medical arena." Tubular metalized fibre braiding allows a bendable and small-diameter product, but the material also blocks much of the noise, according to Stanton.
Demand for off-the-shelf products
While customisation and specialisation represent one part of the market, it is also true that an equally large—perhaps larger—number of device manufacturers are looking for off-the-shelf connector designs suited for a range of applications. Time to market and cost are the primary drivers. While it also offers custom products, ODU (Mühldorf, Germany) believes in the importance of providing a substantial variety of off-the-shelf connectors.
Most customers are looking for power and signal connectors in an array of sizes, according to Richard Harris, marketing special division at the company’s US location. "Size is always an issue. That is why ODU provides large and small connectors with mixed configurations of power and signal," says Harris.
ODU’s new MAC LC line of modular connectors is a case in point. According to Harris, they are able to combine high power and signal into a DIN size housing and frame. ODU’s standard MAC modular system can produce between 100,000 and 1,000,000 mating cycles depending on the configuration.
