Choosing Types of Pins For Your PCB Design
I’ve underestimated the skills and precision it takes to strike a pin on the bowling lane. My first attempt to pick up a game turned out to be a disaster. It took me hours of watching the ball gliding towards the drain before a fluke ended up knocking some pins over. Eventually, the dreaded bumpers came out—I had to admit defeat.
Perhaps bowling wasn’t my game, or, perhaps I’m a terribly slow learner. Either way, it was a mistake to assume bowling pins are like sitting ducks waiting to be gunned down. Thankfully, I never take pins and receptacles lightly in PCB design, even if they seem to be simple mechanical components.
Common Types Of Pins In PCB Design
In PCB designs where there is a need to interface with an external mechanism, you’ll need to factor in pins and receptacles. There are numerous types of pins that are directly or indirectly involved in PCB designs.
After browsing through the enormous catalogs by manufacturers, you’ll find that the type of pins are generally split into the following categories
Turret slotted pins
Solder mount PCB pins
Wire wrap terminal pins
Solder cup terminal pins
Slotted terminal pins
Swage terminal pins
Most of these pins are paired with their receptacles and are made with different materials. Commonly-used materials for producing these pins are beryllium copper, beryllium nickel, brass alloys, phosphor bronze, and tellurium copper. The pins are plated with different finishing materials, such as copper, lead, tin, silver, gold, and nickel.
Some of the pins are soldered or crimped onto wires but pins such as the header, solder mount, press-fit, and turret swatch are mounted on a PCB.
How To Choose The Right Types Of Pins
Choosing PCB pins require no fewer considerations than other electronics components. Oversight in mechanical or electrical details can lead to functionality issues in the prototype or production PCBs.
Here are some areas you’ll need to ponder when choosing PCB pins.
Obviously, you’ll need to decide which type of PCB pin to fit your design. If you’re looking for terminal pins for board-to-board connection, the header pins are the right choice. Header pins are usually through-hole mounted but there are surface-mounted versions that go well for automated assembly.
In recent years, solder-less technology has provided more options for PCB pins. Press-fit pins are the ideal choice to eliminate soldering. They are designed to fit into padded PCB holes and provide a secure mechanical and electrical continuity.
Single row header pins are for board-to-board and wire-to-board.
2. Pitch Size
Some PCB pins are offered in various ranges of pitch sizes. For example, dual row header pins are usually available in 2.54mm, 2mm, and 1.27mm. Besides the pitch size, the dimension of the individual pin and current rating also differs.
The material used in plating the pins may result in different cost and conductivity. Gold plated pins are generally more expensive than tin plated ones but are more conductive.
Designing With Various Types Of Pins
Like any other PCB components, there are some tricks that will save you some heartaches when designing with terminal pins and headers. One of the most important rules is to get the padded hole size right. Always refer to the suggested footprint by the manufacturer for the right size. Padded holes that are too small or large will result in assembly issues.
The electrical characteristic of the terminal pins is also important, especially when high currents are channeled through. You’ll need to allocate a sufficient amount of pins to ensure the required amount of current passes through without causing heat issues.
Mechanical clearance and placement are important for encased PCB header pins.
Using header pins for board-to-board connections can be tricky. Besides getting the alignment right, you must ensure that no high profile components such as electrolytic caps are blocking the gap between two PCBs. The same goes for encased pins that extend beyond the edge of the PCB.
If you’re using through-hole or surface-mounted pins, you’ll want to ensure that thermal-reliefs applied to the ground polygon connected to the pin. This ensures that the heat applied during soldering does not disperse quickly and subsequently affect the solder joint.
When you’re looking into manufacturing and production settings, look no further than the suite of tools available from Cadence. Thanks to Cadence Allegro’s PCB DesignTrue DFM Technology setting thermal relief rules is a breeze. And if you’re using a user-friendly PCB design software like OrCAD PCB Designer, you’ll be able to ensure your design gets out the door.
If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts.