Selecting and maintaining board-to-board connectors

The internal metal contacts of a board-to-board connector are mostly electroplated parts, so the connector must be kept sealed in its storage package and never exposed directly to air. Air humidity can otherwise cause moisture to oxidize the contacts inside the component. The following selection criteria and maintenance practices help protect connector performance and service life.

What to check when selecting

The load voltage of a board-to-board connection must not exceed 50 percent of the connector's rated voltage. The connector is a plug, and the length of the soldering pin exposed beyond the PCB surface must be greater than 0.5 mm. For high-precision board-to-board connectors, choose a type with a positioning pin where PCB space allows, since this simplifies hand soldering. Confirm that the connector has a keyed, foolproof design and that its materials contain no lead.

Contact resistance also matters: for small board-to-board connectors used with low contact pressure, low current and low voltage, choose gold-plated or silver-plated contacts so that film resistance does not affect the signal. Finally, check that the height of the connector after mating clears the solder height of the components around the PCB. The board mating height must be greater than the solder height of surrounding components, leaving a margin and avoiding interference. The PCB may warp noticeably after soldering, so allow for this error.

Daily maintenance

Ensure the board-to-board connector is mounted firmly and reliably. If the connector is not fixed securely, some pins and jacks can separate abnormally during use, interrupting power transmission and signal control in the system.

The contacts are the main functional component, carrying current or signal to the mating connector. Do not use excessive force when plugging the connector in; too much force deforms the internal contacts and shortens service life. A broken or damaged contact renders the whole connection unusable. While the connector is operating it may carry a large current, so do not unplug it at will, which can cause data loss or abnormal termination between devices.

For long-term use, maintain the connector regularly. Dust and debris accumulate on the surface and inside the contacts; if they are not cleaned in time, connector performance degrades. Check for damage and replace any damaged connector promptly to avoid a safety hazard. To reduce insertion and extraction wear on the contact metal, do not plug or unplug the connector more than necessary, and periodically remove the contacts and wipe off surface dirt or debris, for example with a soft eraser, which extends connector life.