When I review drawings at Soulin, customers often send our engineering team a drawing with a pitch and a pin count and figure the hard part is done. I get it, but on paper, a PCB board pin may appear to be simply a small conductive post on the PCB.
But that little pin does a lot of jobs at once. It might be a single contact, a board-to-board post, a wire-to-board termination, a test point, a programming interface, or the male half of a mating pair inside a larger connector system. And because you can arrange pins by pitch, row count, height, and orientation, they give you far more layout freedom than a fixed connector housing does.
Here's the catch, and it's the part I spend most of my time on with customers. The small stuff carries a lot of weight. A pin can pass a bench continuity check and still leave you with weak solder fillets, a mushy mating feel, contact resistance that climbs over time, a cable that won't exit cleanly, or a part you can't rework without pulling the whole board. So when I help someone choose, I'm never looking at the pin by itself. I look at the pin, the mating connector, the PCB process, and where the thing has to live once it ships.
That's usually why people end up talking to us. A buyer, a PCB designer, or a sourcing person shows up with a pitch, a pin count, or a rough footprint, and they want a second set of eyes on whether it will survive assembly and the field. That's the conversation this guide walks through: how I'd narrow the choice by pitch, material, plating, mounting, DFM, and application, using Soulin families like pin header connectors, female headers, board-to-board connectors, and round pin headers.
Quick note on where the advice comes from. Soulin has been making connectors for more than 15 years, we run to ISO 9001 and IATF 16949, and we do our own tooling, molding, assembly, and testing in house. I mention it because a pin choice is never just a catalog choice. It's a tooling, material, and process choice too, so it helps to talk to someone who touches all of them.
A footprint tells you less than you think
A PCB board pin is a conductive metal contact mounted on a printed circuit board. On its own it might be a single terminal, a test point, or a programming contact. Hold a group of pins in a plastic housing and you have a pin header, a female header, a socket, or a board-to-board connector.
The footprint on your drawing shows pad size, hole size, pitch, and body outline. That's the easy half. The real part still has to answer for board thickness and hole tolerance, pin length and how the solder fillet forms, body height and mating clearance, alignment posts and retention clips, plating and mating cycles, housing material against your soldering temperature, the order things get assembled, and how the whole thing holds up under vibration, thermal cycling, and being handled by people who aren't gentle.
So yes, the pin connects the circuit electrically. It also quietly connects your PCB design to how the board gets built and used. If that second role is overlooked, a footprint that passes DRC can still create assembly, reliability, or serviceability problems later.
Start with the walls that won't move
When someone asks me where to begin, I tell them to start with the limits that can't move: board spacing, enclosure height, expected current, mating direction, assembly method, and service access. Lock those first. Only then go shopping for pitch, row count, plating, and packaging.
Do it in that order and you avoid the classic mistake, which is grabbing a convenient header early and then finding out it fouls the enclosure lid, blocks the rework nozzle, or leaves no bend radius for the cable. I've watched good boards get respun over exactly that. Do it in that order and you avoid the classic mistake: selecting a convenient header early, then discovering that it interferes with the enclosure lid, blocks the rework nozzle, or leaves an inadequate cable bend radius. I've seen otherwise sound boards require a layout respin after a right-angle header was placed too close to an enclosure wall: the footprint passed DRC, but the mating cable could not be inserted or routed within its minimum bend radius. Once the mechanical design was frozen, moving the connector required changes to both the routing and the PCB outline.
If you want a checklist of what each choice is buying you:
| Selection filter | Why it matters | Common choice |
|---|---|---|
| Pitch | Density, creepage, routing room, mating compatibility | 1.27 mm, 2.0 mm, 2.54 mm |
| Pin count | Circuit capacity and connector length | Single-row, dual-row, high-pin-count |
| Orientation | Board stacking, cable exit, enclosure space | Straight, right-angle, horizontal SMT |
| Mounting type | Assembly process and retention strength | SMT, through-hole, press-fit |
| Material | Solder heat resistance, dimensional stability, insulation | PA9T, LCP, PBT, PPS |
| Plating | Contact resistance, corrosion resistance, mating life | Gold or tin over nickel |
| Current rating | Power and temperature-rise limits | 1.0 A to 7.0 A* |
| Application | How hard the reliability bar sits | Consumer, industrial, instrumentation, EV, telecom |
*Portfolio-level reference only, not a universal rating. Confirm the exact series, pin count, contact design, PCB copper, ambient temperature, adjacent-pin loading, and temperature-rise test conditions.
Our pin header range is a decent thing to compare against, because it spans most of what you'd be weighing anyway: 1 to 80 pins, one to three rows, SMT or through-hole, straight or right-angle, plus custom. One heads-up though. We haven't uploaded every configuration we make, so if you don't see your combination online, send Soulin the required pitch, pin count, row count, mounting type, plating, drawing or sample, estimated annual volume, and packaging preference. Our engineering team can confirm whether a standard configuration is available or evaluate a custom solution.
Which family fits your kind of connection
The best family really depends on how the connection gets used. A temporary debug point and a serviceable industrial module are not the same design problem, and it's a mistake to treat them like one.
| Connector type | Where it fits | What I'd check |
|---|---|---|
| Pin header | Board-to-board, programming ports, PCB stacking, wire-to-board | Pitch, pin/row count, orientation, current, mounting |
| Female header | The socket side of a removable PCB connection | Mating height, contact style, insertion force, plating match |
| Box header | Shrouded cable or IDC-style connection | Keying, polarization, latch or friction retention |
| Ejector header | Cable connection that needs a stronger hold | Latch design, cable clearance, repeated mating |
| Round pin header | Higher-reliability socketed connection | Machined pin precision, contact resistance, mating life |
If your design needs to come apart and go back together, the female header matters just as much as the male side. Match the pair on pitch, row count, pin count, plating, and height. I've seen mismatched pairs that look like they fit and then hand you insertion force that's all over the place, or contact resistance that creeps up after a few dozen cycles.
When the connection really has to stay solid, say instrumentation, medical, automotive, industrial control, or telecom, take a look at round pin headers. The machined pin gives you a more precise mating surface than a lot of stamped styles, and that precision is what buys you the stable contact. For shrouded, keyed cable work, a box header earns its place instead.
Pitch: it's a layout call and a reliability call
People treat pitch as a space thing, and it is. It's also an electrical and manufacturing thing, and that second part is where it surprises you.
Go smaller and you get more I/O in less board area, which helps compact devices, IoT modules, and comms boards. What you give up is routing room and process margin. Traces get tighter, soldering gets fussier, and there's less space to inspect or rework when something goes wrong.
Go larger and life gets easier. You get more routing room, more creepage, usually more current headroom, and enough space to actually get a probe or a rework nozzle in there. That ease is a big part of why 2.54 mm is still everywhere in general PCB work, instrumentation, industrial controls, and medium-current interfaces. It isn't old-fashioned. It's just forgiving.
| Pitch | Typical use | The tradeoff in one line |
|---|---|---|
| 1.27 mm | Compact modules, comms, high-density signal | Great density, tighter assembly control |
| 2.0 mm | IoT, control boards, compact industrial | A balanced middle ground |
| 2.54 mm | General-purpose, instrumentation, industrial | Easy to route, easy to inspect |
| 3.96 mm and up | Higher clearance or higher current | Room for power and mechanical margin |
Whatever you pick, run the footprint past your actual board fab and assembler. A tolerance can be perfectly legal on the drawing and still be a headache in your specific stackup or on their line. Better to hear that now than after tooling is cut.
Material and plating aren't details to leave for last
I know material and plating feel like a line item you fill in at the end. Please don't treat them that way. A PCB pin isn't just metal. It's a contact system, and the stack decides how it behaves both during soldering and for years afterward.
| Layer | Typical options | What it's actually doing |
|---|---|---|
| Housing/insulator | PA9T, LCP, PBT, PA66, PPS | Heat resistance, insulation, dimensional stability, reflow survival |
| Contact base metal | Brass, phosphor bronze, copper alloy, beryllium copper | Conductivity, formability, spring behavior, strength |
| Underplating | Nickel | Barrier layer that keeps the top plating stable |
| Contact plating | Gold or tin over nickel | Contact resistance, oxidation resistance, mating life, solderability |
| Mating contact | U-type, Y-type, socket, multi-finger clip | Insertion force, retention, wiping action, signal stability |
On the gold-versus-tin question, which I get a lot: reach for gold when you need stable low contact resistance, a lot of mating cycles, or better oxidation resistance. Tin is perfectly fine and cheaper for a connection that gets assembled once and lives in a controlled environment. The right answer follows the application, not the price tag. The plating decision should be based on the required mating cycles, exposure to oxidation, and allowable contact-resistance change—not on perceived premium value alone. Tin is often appropriate for cost-sensitive, mate-once connections in controlled environments, whereas gold is generally preferred for repeated mating or applications that require stable low contact resistance over time.
Let's put a real part on the table
Talking in the abstract only gets you so far, so here's one to check the logic against: our 2.54 mm dual-row 2×10 right-angle pin header. It's a standard PCB pin connector for electronics, electrical gear, and instrumentation. The right-angle layout runs the mating side parallel to the board, which is the clean answer when the enclosure is short on vertical height or the cable needs to exit from the side.
| Parameter | Value |
|---|---|
| Product type | Pin header |
| Pitch | 2.54 mm |
| Pin count | 2×10 pins |
| Orientation | 90-degree right angle |
| Plastic material | PA9T |
| Contact material | Brass |
| Plating | Au or Sn over Ni |
| Current rating | 3.0 A |
| Withstanding voltage | AC 1000 V min/minute |
| Insulation resistance | 1000 Mohm min |
| Contact resistance | 20 mohm max |
| Operating temperature | -40 °C to +105 °C |
Read it the way I would. The 2.54 mm pitch leaves room to route and to inspect. For this series, PA9T is intended for high-temperature soldering, but reflow performance still depends on the exact material grade, component geometry, moisture condition, and qualified time-temperature profile. Confirm the product datasheet and supplier test conditions before finalizing the assembly profile. Gold or tin over nickel lets you balance mating life, oxidation resistance, and cost. The published 3.0 A value applies only to this product and its stated test conditions; it is not a guaranteed current for every pin in every PCB layout. The brass contacts in gold or tin over nickel let you dial in cost against mating life and oxidation. And the 3.0 A rating handles moderate power or a mixed signal-and-power interface, as long as the rest of the design, copper and airflow included, is sized to match. That last clause matters.
Engineering note: Validate current rating at the system level
Treat the published per-contact current as a validation starting point, not a board-level guarantee. Check the exact series and referenced test method, PCB copper and trace width, ambient temperature, adjacent-pin loading, wire gauge and termination, enclosure airflow, and allowable temperature rise. Derating or configuration-specific testing may be required under the applicable product or customer qualification standard.
Footprint and DFM: where the surprises hide
Most connector trouble gets discovered late, precisely because the part looked so simple back when you picked it off a schematic. The footprint is where the hidden stuff surfaces.
Hole, pin, and board thickness have to agree
Through-hole parts live or die on the relationship between finished hole size, pin size, plating thickness, and board thickness. Too tight and assembly fights you. Too loose and the solder joint and the mechanical hold both suffer. Pin length ties into board thickness as well. Too short and the fillet is weak. Too long and you've got clearance grief on the far side of the board.
Alignment posts and retention features are great until they push your tolerances
Posts, press-fit sections, board locks, and clips all help, but they lean on the PCB fab. Check your non-plated holes, plated holes, edge distances, and keepouts before you release. And if one master drawing covers a whole family of part numbers, which parametric families almost always do, confirm which dimensions apply to your exact part number and not the cousin two rows down.
Connectors live in three dimensions, so leave room to work
A footprint can sail through DRC and still fail on the line or in service because there's nowhere to plug, unplug, latch, tighten, probe, or rework. The clearances I'd walk the layout for are finger or tool access for mating and unmating, cable bend radius, latch travel, adjacent component height, probe access for test, rework nozzle room, and the enclosure walls and hardware. This bites hardest on right-angle parts, cable connectors, and high-pin-count board-to-board stacks sitting near the board edge.
Match the part to how it'll be assembled
SMT headers love automated placement, but they want good coplanarity, sane paste design, and packaging like tape-and-reel or pick-and-place caps. Through-hole may mean wave or selective soldering, or a second operation. Press-fit needs controlled insertion force and a tight finished-hole tolerance. My honest advice is to ask your assembler which process they'd rather run before the PCB freezes, especially for a right-angle part near the edge. The most robust connector decisions are made while the PCB layout, mechanical design, and assembly process can still be adjusted together, before the design is frozen.
Three cases where the pin is part of something bigger
A board pin almost never works alone in the finished product. The real question is how it behaves inside a larger architecture, with FPC cables, wire harnesses, board-to-board stacks, external I/O, service access, and whatever the environment throws at it. Three of our application areas make good reference points.
Instrumentation and test equipment
Think test and measurement gear, industrial power units, and data acquisition. A display might run on FPC/FFC connectors, the measurement boards might stack through pin headers and female headers, and power might route through a custom harness. Here the pin choice isn't only pitch. It has to protect measurement stability, keep the unit serviceable, and stay repeatable in assembly. See our instrumentation solution.
New energy and EV charging
BMS, charging stations, on-board control units. Now the connector scheme is up against thermal cycling, outdoor exposure, vibration, and signal routing that can't drift. Pins and headers often work alongside ejector headers, wafer connectors, RJ45, SATA, DIN 41612, and harnesses, so retention, plating, current margin, and assembly consistency all get checked as a set rather than one at a time. See our new energy and EV charging solution.
Industrial automation
PLCs, servo drives, HMI panels, and robotics operate in factory environments with vibration, EMI/RFI, dust, heat, and service constraints. A connector suitable for a small consumer device may not provide the mechanical retention, shielding, environmental tolerance, or maintenance access required in a control cabinet. For board pins, that means looking beyond the headline datasheet rating to mating cycles, board support, cable pull direction, contamination exposure, and the planned rework path.See our industrial automation connector solution.
A checklist to run before you lock the footprint
Name the job: board-to-board, wire-to-board, test, programming, service, or power.
Pick pitch and pin count from density, current, clearance, and routing.
Choose orientation: straight, right-angle, horizontal, vertical, or custom.
Decide SMT, through-hole, or press-fit based on your assembly flow.
Confirm the housing material handles your soldering temperature and stays dimensionally stable.
Match contact metal and plating to signal level, mating cycles, and environment.
Verify current, voltage, contact resistance, and insulation resistance.
Check the exact footprint against your fab's and assembler's rules.
Reserve room for mating, latching, cable bend, probing, and rework.
Validate samples before volume, especially anything customized.
FAQ
The short version
Board pins are small, but they set the rules for board spacing, assembly access, mechanical hold, serviceability, and stable signal or power. Pick one well and you start with the job of the connection, filter by pitch and mounting, then check materials and plating, then hold the footprint up against your real DFM limits. Tie it to the actual architecture and the right choice practically argues for itself.
If you're a Soulin customer, the fastest next step is almost always a quick technical review. Send us the drawing, stack height, current requirement, mating connector, assembly method, and target environment, then confirm samples before you commit to volume. That's how a board pin goes from a catalog guess to a connector you can build, inspect, and support for the life of the product. Talk to the Soulin team when you're ready.
