Connectors are getting smaller and smaller. The question is, how small is the connector? To answer this question, it's important to remember that applications that use connectors require many performance and reliability requirements, especially in medical devices.

Figure 1. The softness and feel of the cable that comes with the connector can help ensure that the patient is served in a quality environment.

Connector-specific applications (especially reduced-size connectors) have grown rapidly over the past five years. Now, this has facilitated rapid changes in technological advancement, starting with new solid model design and performance prediction software that will help new advances in circuit-chip technology. These changes help improve performance and improve functionality. These evolving circuit chips require lower voltages and currents, but run faster, store and process more data, and extend battery life.

The new software also enables designers to simulate smaller connector options, from simple CAD rendering to product manufacturing. The new housing size and shape can be quickly changed in minutes and cut with a CNC machine. These changes provide designers with a faster prototyping cycle at a reasonable price, and these designers need to squeeze every millimeter of space from their interconnect system. Often, designers choose standard connectors to start circuit testing, but eventually find that they need custom design connector variants.

Determine size requirements

Connector size requirements are typically based on a number of key application factors and performance limitations, including current load, signal integrity, environmental conditions, and circuit mobility. Many other factors include awareness and compliance with bioprotection, minimal open gaps in connected pairs, and creepage (which can hoard contaminants and specific materials for sterilization).

Signal integrity

 As connectors and circuit modules squeeze into more compact spaces, the circuits must still operate independently of adjacent circuits. The design must include protection against signal crosstalk and protection from electromagnetic radiation or other signal noise inside and outside the receiving system. Some modern shielding techniques are usually built into the connector. New shielding materials typically combine braided wire and aluminum foil and are wrapped around the length of the cable within the jacket material. In addition, a small ceramic filter can be included in the connector housing for selecting which frequency signal can pass through the cable and which can be discharged to ground.

Environmental conditions

The rugged connector design delivers high performance in extreme environments and is typically controlled by specifications to ensure continuous signal flow during high shocks and vibrations, as well as performance during extreme temperature cycling. For example, a blood perfusion monitor approaches the patient during surgery to ensure that internal bleeding from the surgeon from the operating table does not occur. A miniature cable (sturdy and durable, medical-grade silicone overmolded) has a connector at the end for use with disposable tubing. The catheter is located inside the brain and is small and delicate. In this case, the main cable protects the small conduit from accidentally moving or pulling during its use. Until the end of the catheter is removed and discarded, the connector and cable assembly are pulled out for rigorous sterilization and cleaning. In some portable applications, such as neonatal monitors, electrocardiogram systems, and other skin-sensitive detectors,

Connectors often face some additional challenges. Protection ratings (IP) such as protective seals and resistors are critical in portable cables and equipment. Omnetics Connector's IP68 Nano-Circular series is an example of how to solve this problem on the market today. These connectors are protected from the smallest form factor and remain sealed. Choosing the right materials and processing can also produce connectors that exceed IEC 60601 specifications and prevent any leakage or shorting to the patient being treated. Elastomeric seals are typically built into the connector to ensure that no moisture or dust can pass through the connector and into the circuit. As connectors continue to be miniaturized, smaller and smaller seals will be required.

Current load

Each connector contact must provide a low-resistance interface with it and carry enough current to meet the circuit it is servicing. Fortunately, advances in chip technology have reduced the amount of current, and as long as they remain within safe limits for good performance (some changes in power and signal surges), interconnect components can be shrunk. The current limit is usually determined by the wire diameter of the cable itself, since the wire length multiplied by the resistance will determine the performance and thermal capacity of the interconnect system. Using the low resistance line option can handle enough current to run the device, which is often critical. So many machines often run at the same time, and high drag can slow down the signal processing unit or delay triggering an emergency alarm. When the connector has a matching impedance, it provides significant clarity for the indoor display.

Circuit mobility

Connecting active chips directly to portable devices is an example of today's demand for miniaturization. Applications such as robotic hands and medical probes are an early example. Transcutaneous connectors are now used in neuropathic management devices, and miniature connectors are being used in cochlear devices. Even smaller connectors are used in neuromonitoring and control devices for remote function control circuits. As medical designers face an attempt to focus more on portable electronics, the cost of introducing smaller connectors appears to be focused on brain mapping and neural sensing devices used in Parkinson's research. It is here that we need to reduce the size. Evaluate the potential shape, fit, and function of the standard design and then customize it with a solid model design to meet dimensional and reliability requirements. Pin and socket sizes can be reduced to the minimum size that meets these standards and can still be squeezed into the allowed space. Circuit design can also reduce the number of leads by combining signal systems. Some connectors are being used within the medical device during device assembly. These connectors are paired once or twice during their lifetime and the design may focus on the long-term reliability of equipment shock and vibration. Recently, the development of combining two or three connectors into one connector has become a focus. Instrument designers have found that they can reduce the number of cables connected to the machine by requiring the connector to have both a power section and separate signal processing in the same connector. This saves space, weight, and in many cases saves costs. Instrument designers add multiple contact types to a single connector and can choose to use it in one housing: 1, 3, 5 or 10 contacts. This option allows OEMs to connect power and signal lines to each other, saving design time and reducing the number of spare cables required for inventory. Challenges and Opportunities Today's miniature connectors offer superior performance, charging power and signal routing in one component. This method of interconnecting with a single flat strip or lead frame opens the way for high speed digital signal processing. Careful use of shapes and spacing allows for another level of high-density interconnection. As circuit speeds increase and size decreases, the use of unique low dielectric strength insulator materials also paves the way for smaller connectors. Board-to-board connectors that use pin or pressure connections take up very little space and produce only minor aberrations in signal transmission. The use of small connectors remains to be seen. Larger connectors are currently being replaced by smaller, lighter micro-circular connectors that use 0.050-inch pitch, and those same 0.050-inch pitch solutions are being replaced by 0.025-inch pitch nano-variants. Multiple high speed signals can also be processed.