There are hundreds of thousands of connectors on the market, so if you feel overwhelmed when it’s time to pick the right one to interface with your printed circuit board, you’re in good company. Connectors are produced in families and assigned different part numbers that correspond to their respective quantities of pins and contacts. That drives up the number of choices, making the selection process even more daunting.
If you’re trying to create a printed circuit board design that will work with a certain connector, we recommend that you create a working printed circuit board footprint. You can then create a mechanical mockup to verify that the connector is compatible with your design.
Follow these basic steps to begin narrowing down the connector choices.
Consult the product description. Read the description thoroughly, watching for the following:
- Maximum current capacity. Stay well below this current capacity to avoid fires in the wiring.
- Hot-plugging threshold. Most connectors aren’t meant for hot-plugging (the practice of unplugging something while the power is still on). If your design needs to support hot-plugging, look for special connectors designed for this purpose.
- Cleaning specifications. Connectors get grimy over time, so find out the best way to de-gum them. Choose a connector that can tolerate isopropyl alcohol and doesn’t require a lot of fussy cleaning techniques.
- Heat resistance. If your connector will be exposed to surface mount soldering, the plastic on your connector could melt. Make sure that potential connectors can handle the heat they will have to stand up against.
Assess contact resistance. Once you get the connector, you will want to measure the contact resistance. You can do this with the assistance of an Ohm meter that can gauge resistance down to the milli-Ohm. If you don’t have an Ohm meter, splurge and purchase one. You will be surprised at how often you use it. Make sure that the connector you are considering has repeatable resistance that does not change much—even if you jostle it around a bit. If your power pin can’t handle enough current, opt for a higher-current connector or use a series of parallel pins.
Can I go with the lowest bidder? With connectors—as with many things in life—you often get what you pay for. Connectors can make or break a design. Insist on high quality and be willing to pay a little extra for it.