Best Practices for Integrating Pin Receptacles in Your PCB Layout

PCB design is an area where many electrical engineers struggle to find success on the first design and manufacturing run. For designers working on high-reliability designs, pin receptacles are often used to form important interconnects, most often for transferring power around a system.

This article will discuss some of the important guidelines to follow when using pin receptacles in a PCB. These parts have design for manufacturing (DFM) requirements that should be followed to ensure maximum reliability and compatibility with standard processes. We’ll cover some of the most important guidelines in this article.

How to Use Pin Receptacles in a PCB Layout

Pin receptacles can be used to form a variety of connections including board-to-board, board-to-device, or board-to-wire. The use of pin receptacle components in a PCB must follow a set of rules surrounding footprint creation (e.g., hole size and pad size), routing for power and signal, and board thickness limits for some components.

Routing Power into Pin Receptacles

A very common application of pins and receptacles in a PCB is for making reliable power connections, although they can be used to transfer signals in certain applications. The power and signals should be routed to pin receptacles in accordance with industry standard guidelines and practices. While signal routing into pins is relatively straightforward, routing power into pin receptacles requires an understanding of current handling in the mated interconnect.

Heat will be generated when current flows in the pin receptacle connection coming into the PCB, and higher currents in the pin receptacle will require wider traces or large copper pours on the PCB. To ensure heat in pin receptacles is managed effectively in power connections, the receptacle can be used as follows:

Run multiple pins in parallel to reduce the current per pin/receptacle
Ensure the PCB assembly operates at lower temperature
Use heavy copper in the PCB routing to provide a heat sinking effect

Testing may also be necessary to ensure your design operates at your temperature target. During the PCB design phase, a designer can leverage the IPC-2221 or IPC-2152 standards for sizing conductors that connect with inserted pin receptacles.

Hole/Pad Sizing in PCB Footprints

Every component in a PCB layout needs to have a footprint. For through-hole components, this would include a mounting hole (either plated or non-plated), an annular ring (for a plated through hole), and a solder pad (if required for the assembly process). For surface-mount components, this would just be the solder pad.

Suppliers often provide a general footprint recommendation on the product’s webpage or datasheet. However, this may need to be adjusted depending on application-specific factors or relevant standards (e.g. IPC 2222). Consulting with a PCB manufacturer would be the best way to ensure all requirements are met.

Board Thickness Requirements for Pins Receptacles

The board thickness required for mounting a pin receptacle onto a PCB will depend on the component’s termination method:

For surface mount components, the PCB thickness does not play a role as the component will just be mounted to the surface.
For through-hole components that are soldered, a maximum board thickness may be required to ensure a minimum amount of component protrusion through the PCB; review any applicable PCB standards to see if this applies.
For press-fit components, the board should have a minimum thickness such that the press-fit feature is completely captured inside the PCB. In general, ideal positioning of the press-fit feature in the board is centered within the thickness dimension of the PCB.
For swage mount components, a board thickness is often recommended to ensure a proper swage joint. In general, the pre-swaged terminal shank should extend at least .022" above the circuit board surface so there is sufficient pin material to form and flare.

For maximum mechanical reliability, press-fit, swage fit, or through-hole solder mount would be the recommended options for mounting pin receptacles into a PCB. However, the forces on pins and receptacles depends on several other factors, such as the weight of the interconnected boards and how they are mounted in a housing.

To gain the mechanical advantages of press-fit pins and receptacles, a receptacle type with polygonal mating surfaces can be used. For example, a hexagonal cross-section feature in the receptacle gives six contact points along the outside of the pin surface during insertion into the PCB. The sharp points on the polygon feature cut into a plated hole in the PCB, but this leaves the remaining conductive hole wall intact. This provides strong anchoring at multiple points in the plated through-hole.

Choosing a Reliable Pin Receptacle Partner

These aren’t the only design rules a PCB designer must consider when working on high reliability systems, but they are a good starting point for working with pin receptacles in a PCB. To fully evaluate your assembly and the reliability of pin connections, make sure your design is mechanically tested against industry standard qualification metrics.

The connector experts at Mill-Max are here to partner from design through manufacturing. Contact us today to get started on your next project.