Choosing wire-to-board interconnect options

Paul Boughton

Engineers today have several wire-to-board interconnect options available to them. One main driver is whether the design requires field repair/termination or if this connection is made once and never touched again. While it is convenient to design for a removable/reworkable option, that choice can add additional costs and complexity to the project.

Traditional wire-to-board connection options consisted of either permanently soldering the wire directly to the PCB or utilised two piece solutions (like two piece headers) that were reworkable.

The headers had one piece permanently connected to the PCB during assembly and the second piece that contained the wire connections in the form of a cable.

The rework friendly two piece connection scheme worked well as long as space and budget were available. Modern designs require much less space and also are more ‘disposable’, the product is much more likely to be replaced then reworked. This fact seems to support permanently soldering wires directly to the PCB, but the increasing usage of integrated metal substrates and expected reliability of modern electronics introduce significant challenges for this approach.

This space restraint now has engineers challenged to incorporate new interconnection that offer reliable cost effective alternatives.  Most of the designs only require a power connection to the PCB, so there is only a need to terminate two wires. The limited number of wire connections make the use of individual terminals an attractive option. Zierick Manufacturing produces a wide variety of UL Recognised options to connect discrete wires to circuit boards.

Designers have the ability to terminate wires with no additional preparation (insulation on), the insulation removed or a terminal attached. Solutions are also available for applications requiring serial/pass-thru connection for cases were multiple PCBs need to be terminated.

In cases where the insulation is left on, Zierick offers Insulation Displacement and Insulation Piercing options. Its Torsion IDCs are designed to insure a pre-load force on the conductor that provides excellent shock and vibration performance for critical applications; as well as the ability to use the same connector for a range of wire gauges.  Our patented SM Insulation Piercing Terminals provide connection to the wire while providing additional strain relief during the wire termination process.

For applications that require the wire to have the insulation removed (stripped and tinned), Zierick offers wire gripper receptacles. These gas tight terminals can be used with both solid and stranded wire, it is recommended that the stranded conductor be tinned for best results.  We offer versions for various wire sizes and configurations to allow for wire placement horizontally, top entry or bottom entry.

In cases where a terminal is attached to the wire, Zierick offers pins, blades or receptacles depending on specific requirements and are available for both Surface Mount and Thru-Hole boards. These options also allow the connection of odd form components (such as motors, sensors or relays) to the circuit board.

The use of discrete terminals can also further lower production costs since they are offered in configurations that include standard plastic pocket tape (tape and reeled) and continuous strip versions that can be placed with termination equipment in both thru-hole and Ssurface mount applications.