Connectors are the unsung stars of both a product and its hardware development. Any Apple user knows the romantic tale the company has spun from infatuation with the first magnetic power connector through the betrayal of the 3.5mm jack to today’s ‘it’s complicated’ status thanks to the baggage their dongles create in pursuit of beauty.
Product developers have similar emotional experiences with their prototypes. An unreliable connector that has exceeded its insertion or flex rating during testing can cost days of troubleshooting. Manually crimping or soldering contacts is annoying and sometimes ineffective all because nobody will buy a $1,500 tool to crimp 10 prototype wires. And then, there’s the supply chain woes and knock-offs of questionable quality to battle. Thinking about connectorization early without getting prematurely attached to a specific connector pays dividends for the life of the product.
Connector selection is often assumed to be a simple and quick matter on project Gantt charts – no more difficult than picking an LDO voltage regulator. In reality, it is a collaborative effort between the electrical, mechanical, and UI developers with a dozen variables to weigh which can’t all be evaluated using a spec sheet. As with any project, building a target vision early is critical. Some typical questions to ask would be:
With a vision set, a set of contenders needs to be identified. The best way to go forward is to flip through a catalog (if they are found) to see what is out there and what the terminology is used to describe the types of connectors to consider. Digital catalogs are another solution source, as are vendors’ demo kits and FAEs. In any case, picking from a menu is the easiest starting point. A list of reasonable possibilities can be created based on written electrical and mechanical specs required, such as:
Anything on that list or that could be even close, should then be purchased so everyone on the team can test out the connectors in person. This includes the entire connector system – the header, the contact, the housing, different variants with shrouds/locks, etc… It is often that a team won’t know what they need until they see it. After all, connectors live and die based on real-life ‘feel.’ It is also possible that nothing feels right and the team needs to go back to the drawing board. This is where visits from vendors and sales engineers can be particularly helpful since the team will have an idea of what is, and is not good.
With a short-list of connector systems defined, it’s helpful to consider other secondary aspects of the decision not related to the connector itself:
Note that a given connector may produce all ‘wrong’ answers from this secondary list, but if it’s the only one that can do the job, it may still be the ‘right’ choice. Similar to how a space rocket is nothing but expense and risk and hassle, that is until it puts mankind on the moon.
Blending together the performance, appearance, and feel of a connector system is truly an art of understated opulence. Design teams should celebrate that the highest praise of a connector is being so seamless that its use goes unnoticed.
Would you like to find out more about how Altium can help you with your next PCB design? Talk to an expert at Altium or read on about modeling and placing connectors within Altium Designer®.
With an endless variety of electric connector types and several crucial criteria to consider, choosing the right one can be downright difficult. However, choosing the right connector is the most efficient and reliable way to modularize, improve or downsize a system so that it runs smoothly without needing frequent repairs.
How many signals are there in total?
What currents, frequencies, and voltages are they carrying?
Are your signals analog, digital, or a combination?
The combination of signals has an impact on the connector type, pinout, and wiring. For instance, high-frequency signals may need coaxial connection and low-level analog signals may need shielding.
Certain signal combinations cannot be included in the same connector. If high voltage pins are involved, you may need to take creepage and clearance distances into account. If there are high current paths, you may need multiple pins and bigger wires. Depending on your unique case and design requirements, you might also need a custom solution.
Current rating is the most vital criterion for selecting electrical cable connectors. It is a measure of the amount of current that can flow through a mating terminal and is ideally stated in amps per circuit. The flow of current should be adjusted or derated on the basis of the number of circuits in a given housing according to the rise in temperature of the adjacent terminal.
The size and weight of electrical cable connectors and terminal connectors have reduced in correspondence to the reduction in space available for them. However, their ability to withstand an increase in plugging and unplugging frequency has increased considerably. So, depending on the situation that applies to your project and its design needs, you may need to look for more options in electric connectors.
Most electric connectors are subjected to extreme conditions like vibration and shock. Electric cable connectors and terminal connectors that are designed for extreme conditions and hazardous environments incorporate special features that resist vibration and shocks and withstand extreme temperatures.
So, choose your electric connector depending on the location of your electric connector, the proximity to a heat source, operating temperatures, and the frequency of plugging and unplugging.
Reliability is another vital factor that needs to be considered when buying electric connector. However, reliability is a complicated concept which depends on several factors. Accurate figures are difficult to determine but some connectors come with a specification for mean time to failure. This serves as a guide for selecting the right electric connector for any application.
Certain environments require protection against invasion of combustible or inflammable gases, vapors, dust or liquids. Electric connectors come with environmental sealing options that are effective against unexpected splashes. Once you know the level of safety required, you can verify the IP rating number in the IP code system and know if you are investing in the right electrical connectors.
Environmental sealing is a very important criterion for safer workplaces, especially in stringent environments like aerospace, space, underwater and medical and food applications.
Terminal materials and plating are often the last factors to be considered but since most electric connectors are made using nylon plastic, they have inflammability ratings for high resistance to flame continuance. The standard options available include tin, lead and select gold which are suitable for most applications. Base materials are typically available in phosphor bronze or brass as they offer excellent strength and current-carrying capabilities even with prolonged exposure to high ambient temperatures.
The price of electric connector is typically calculated based on the total cost which includes the receptacle and the plug, the cost of terminal connectors, and the labor cost for attaching the electrical wire to the terminal and inserting it into the housing.
The criterion that matters the most to you will dictate the type and size of the electric connector. Other factors that you need to consider here include the operating voltage, the size of the wire, the configuration, engagement force, and the size of the circuit.