What Is a Board to Board Connector?
Board to board connectors allow PCBs to connect with each other without the need for wiring harnesses. They are available in a variety of pitches, densities and stack heights.
Choosing the right one requires a thorough understanding of the different factors that affect performance. This includes pin pitch, plating options and routing density.
Pins
Typically made from copper alloys, pins (or contacts) in board to board connectors are driven into interference fit holes for strong semi-permanent connections that resist vibration and hold well. Plating is another factor that affects the connector’s performance, life cycle, quality, and cost.
Different copper alloys offer different levels of conductivity and physical endurance. Some are coated in nickel for better corrosion resistance, while others are plated with gold or silver for greater luster. Silver and gold are more expensive than tin, but they can also provide improved conductivity.
When selecting a pin, consider its material, length, and thickness. Steel and stainless steel are good board to board connector choices for heavy duty applications, while tin and brass are more suitable for light to medium use. Regardless of material, all pins should have smooth pilot sections that allow for accurate alignment before driving.
When installing connectors, be sure to follow the manufacturer’s datasheet for recommended PCB pad layouts, soldering temperatures and times, and termination methods. In addition, polarization and keying features can be incorporated into connectors to ensure they are inserted in the correct orientation. This prevents the accidental application of excessive force that can damage the connector or device. These features can include asymmetrical shapes, notches, or tabs that only allow the connector to be inserted into the mating receptacle in one direction.
Insulators
Insulators hold the pins together to form the connector. They are made of plastic, wood or other materials that do not allow heat or electricity to pass through them. They also protect the connectors from environmental elements such as moisture and oil, as well as EMI and RFI (radio frequency interference) and ESD (electrostatic discharge). Insulators are available in various forms including molded or machined plastic. Different insulators have different characteristics such as strength, weatherability and chemical resistance.
Depending on the application, a board to board connector may need to accommodate different sizes and shapes of PCBs, or varying PCB stack heights. It is possible to configure board-to-board connectors with different insertion forces and numbers of positions to accommodate these requirements.
High-speed data transmission applications require a connector solution with good contact reliability. Increasing the number of contacts per terminal increases the reliability, but this has an impact on signal integrity and can reduce high-speed performance.
JAE’s AX01 floating board to board connector series solves this issue by using a stub-less two-point contact structure that does not hinder the flow of electric current. This enables the floating board to board connector to absorb tolerances during the assembly process and provides high-speed transmission performance while maintaining excellent contact reliability. It is also compatible with industry standard backplane, mezzanine and coplanar connections.
Headers
Board to board connectors deliver a simple, robust and low-cost solution for routing power and signals between individual printed circuit boards housed inside products. They do this by leveraging a combination of receptacle terminals, receptacle housings and headers. The pins that connect to receptacle terminals or receptacle housings are commonly called headers. Headers are available with a variety of different pin pitches and features, including gender.
Male pin headers consist of one or more rows of metal pins molded into a plastic base. They are commonly seen on Arduino boards and kits. They can either be at a right angle to the PCB surface (also known as straight) or parallel. They come in a number of different pin pitch values, with the most popular being 0.1″ (2.54mm) single or double row connectors, which are standard breadboard compatible.
Female pin headers are the sockets that male headers plug into, and are typically found on the opposite side of a PCB from the pin-outs on the silkscreen. They may be plated with various alloy materials that offer different levels of conductivity performance, physical endurance and quality. They can also be coated with finishes that protect against corrosion or enhance solderability.
The headers may be through-hole or surface mount, depending on the size and complexity of the circuit board. Thru-hole pins are installed through drilled holes on the PCB, and they provide a more robust physical connection. Surface mount headers are used on smaller PCBs and are often soldered directly onto the board. Both types of headers are designed with a corresponding receptacle on the other side, enabling them to couple together successfully.
Gender
Board to board connectors use male pin modules and female socket modules to link circuit boards together. These small board-to-board connectors can be used in a wide variety of applications, including mobile electronics, automotive, and industrial automation. They are offered in through hole format for manual insertion into PCBs and SMD Board-to-Board Connector Supplier options for automatic pick and place and reflow soldering. These board-to-board connectors are available with a variety of pin counts, from 1mm to 0.8mm pitch, and come in various housing types, including flame-retardant polarized housings.
In general, gender specifications in electrical connectors are determined by the relative positions of their protrusions and receptacles. Male connectors are referred to as plugs and female connectors as sockets, although informal gender-based usage has a more direct association with genitalia and sexual intercourse than does the technical meaning of the designations.
When it comes to AC power connections, a strict gender assignment is implemented to enforce the principle of one-way flow and to prevent undesired configurations that could lead to dangerous conditions such as electrical shocks. For this reason, it is illegal to make or use gender changer fittings for AC power connections to consumer-level equipment. However, for other connection schemes, gender assignments are less rigid and may be based on other considerations, such as the need for physical protection or the desire to conserve space in tight circuit spaces.
