Features

The Right Connections Help Medical Equipment Designers Satisfy Demanding Applications

Other Interconnect Considerations

Medical instruments used in healthcare facilities can often mean the difference between life and death. In these situations, cable interfaces must allow fast, foolproof interconnections by doctors and technicians not well versed in electronic technology. In such critical care usage, connector contacts must align easily, provide proper polarization, and have a housing with quick-release latching and robust strain relief for the cable.

In addition to efficient assembly for reduced end product cost, the connector design should provide foolproof shielding and grounding to ensure safe connections. One way this is accomplished is through a design that provides automatic grounding of protected earth (ground) terminals when a completed frame is assembled into a metal housing. In this type of design, the cable shielding can be attached to protected earth terminals to ensure grounding to the connector frame.

Weight and portability requirements continue to be a trend in medical electronics that push the boundaries of extreme component density, without sacrificing the robustness of connector interfaces. These design goals are essential in advanced miniaturization efforts for portable devices. Still, dense electronics and compact size are crucial in many medical devices and systems, not just ones that are portable. The connectors used in instruments for both types of application must have all the characteristics just mentioned, including connectors used inside instruments.

One example is mezzanine connectors used on PCBs for routing a variety of signals and power. Miniature, robust connectors using surface mount technology (SMT), like the one shown in Figure 3, have high contact density that helps maximize space utilization inside instruments. They are available for “board-toboard” and “board-to-cable” applications. In the latter, insulation displacement connectors for ribbon cables provide a high degree of freedom to system designers. These scalable mezzanine connectors provide a robust interface that can absorb considerable mechanical stress on the solder contacts, allowing repeated insertion and removal.

Surgical Robots Push Interconnection Capabilities

Nowhere is the demand for connector sophistication, complexity, and reliability greater than in robotic surgical equipment. The precision, quality, and control required in these systems are extremely high and can be met only through sophisticated interconnections. In addition to high performance features, connector solutions must come in packages with reduced size and weight. These qualities are crucial, as the safety of the patient depends in part on the surgeon’s ability to easily maneuver robotically controlled instruments.

High speed analog and digital signaling is commonly utilized in surgical robotics. The radio frequency (RF) interconnection systems used in these applications have many of the same requirements as the mezzanine connectors mentioned above. Designers must strike a balance between high performance and superior reliability.

Designs like the one shown in Figure 4 can handle high frequencies while simplifying board construction. This type of interconnection design offers high density with the reliability of blind mating features. Because the design also allows ganged connectors for RF, power, and data on the board, this modularity is of great interest to designers concerned with a combination of safety, dense packaging, and easy assembly.

The article was written by Edmund Garstkiewicz, Market and Applications Manager for HARTING North America, Elgin, IL. For more information, visit http://info.hotims.com/40438-163.