As electronic assemblies continue to shrink in physical size, they are offering an increasing number of functions. Traditionally, adding more capabilities would mean using a physically large printed circuit board (PCB) and housing to accommodate the additional components.

Board To Board Connectors for Reliable & Cost-Effective Electronics Assemblies

This results in more space, weight, and product costs. However, designers and manufactures can use more efficient ways to build smaller assemblies that utilize the available space to the maximum. Instead of using just one large board, the alternative is to use multiple smaller PCBs; some stacked on top of the others or mounted perpendicular to take advantage of the vertical space. Such designs have high component densities and a small footprint.

While manufactures can interconnect the boards by soldering them together, a more convenient and flexible approach is to use board-to-board connectors. These allow easy assembly and a means to establish secure electrical connectivity between two boards. Generally, the connectors link the boards and circuits electrically without wires or additional soldering. One of the mains benefits of using board-to-board connectors is the flexibility and ease of assembling and disassembling. Consequently, it also makes it easier and less costly to upgrade boards or replace faulty PCBs.

The board-to-board connectors have a wide range of applications, including connecting PCBs in portable devices, wearables, industrial robots, high-speed trains, server storage systems, and other multi-board applications. Besides delivering power, mixed-signal connectors may also provide a reliable data transfer between PCBs.

To support various board designs and orientations, there is a wide selection of connectors. These may differ in terms of orientation, sizes, pitch size, construction material, current carrying capacity, signal integrity, and more.
A common type for small devices with high circuit density is the elastomeric board-to-board connector.

Connectors by function

The design, size, and capacity of a board-to-board connector are largely dependent on the area of applications. Some of the considerations when making the connectors include the current carrying capacity of the conducting layer or pins, operating environment temperature, signal handling, physical size, and more. Additionally, the insulating material and ability to withstand environmental conditions such as corrosion is a factor that influences the insulating and the conductor’s plating materials. That said, below are some of the popular board-to-board connectors.

Power connectors

Power connectors provide a reliable electrical link with the capacity to deliver high currents. It delivers the electrical power from one PCB, such as a power supply unit, to the other board. Ideally, the size and design of the power connectors vary according to the current in the target applications. High currents require thick conductors, large surface area, and excellent electrical conductivity properties. Additionally, the connectors may have a locking system to ensure that it remains in place, hence preventing loose connections and arcing.

Mixed signals connectors

The mixed-signal connectors combine the ability to carry analog and digital signals. Sometimes, this may include DC and AC voltages and the design for these connectors require careful consideration, especially when dealing with high-speed signals. In such a case, there is a need to consider interference from the different signals. The connectors come in different sizes and designs depending on the applications. For applications with very small currents and physical spaces such as wearables, smart watches, and similar devices, they rely on micro connectors since the standard types may not fit physically.

High-speed connectors

High-speed board-to-board connectors have superior construction to prevent any signal losses or coupling issues at the interconnections. The connectors have highly conductive surfaces for proper contacts and signal integrity. Additionally, they have a much larger overlap surface to ensure zero resistance, hence maximum contact and signal current.Mezzanine connectors are ideal for high-performance interconnections that support typical transfer rates of 28+ Gbps. Further, the design is optimized to ensure signal integrity.Ideal board-to-board connectors should enable high-speed data transfers between boards. These should have high signal integrity to prevent introducing noise and other issues that affect data integrity. Typical applications for such high-quality board-to-board high-speed connectors include computing, communications, research equipment, and many more.

RF Connectors

Radio Frequency (RF) connectors are usually suitable for a wide range of communication applications. Today, there are different RF connector types available in various configurations. The market for RF board-to-board connectors continues to grow due to the increasing miniaturization of wireless modules and systems. Some designers are doing away with the traditional RF cable assemblies instead of replacing them with modern and smaller-sized board-to-board RF connectors. Not only are these smaller in size, but also capable of handling higher power levels up to above 200W. Consequently, this saves on space, weight, and cost without compromising performance. It even leads to better performance. 

A typical board to board connector has features such as:

  • High signal integrity.
  • A wide frequency range - covering the entire frequency spectrum of the target application.
  • A typical connector may have a range of between zero and 18GHz.
  • Vibration and shock-resistant.
  • Reasonable temperature range with typical values being -55 °C to 125 °C.
  • Suitable for the board to RF module or board to board connections or interconnections.

Elastomeric board to board connectors

These are electrical connectors with alternating paths of electrically conductive and insulating materials. Although the design may look simple, it provides a solution to a wide range of connections, including obsolete and difficult-to-get custom connectors. In practice, the conductive properties of the electrically conductive path, as well as the materials, may vary according to the application. The stripe pitch or distance between the connective paths, and the overall dimensions such as length, width, and height may vary depending on the specific application.

Further, the electrometric connectors provide high-density redundant paths such that at least one of the conductors will make contacts and complete the target circuit path. Usually, these connectors are useful devices for making highly reliable connections. Once placed between two electronic systems, for example, a PCB and an LCD, the design allows at least one of the conductive layers will make good contact with the aligned or matching contact pad. Similarly, at least one non-conductive layer will insulate the adjacent contacts or circuits.

The flexible connectors are suitable for applications exposed to vibrations and shocks. In practice, the construction material for the elastomeric core is silicon rubber, the conductive paths can be fine filaments of metallic (gold or gold-plated copper) wires, or layers of carbon-filled, silver-filled, or gold-filled silicone rubber.

Carbon filled connectors are common in LCD applications such as TVs, LCD displays and other devices. These devices use very low currents that carbon-filled connectors which have relatively high resistance can handle. For other board-to-board connections, where low resistance connections are required such as memory cards, computer modules, chip-to-board connections and more, wire-based connectors are recommended.

Benefits of elastomeric connectors

Elastomeric connectors are less costly and do not require any tooling. As such, they end up lowering the manufacturing costs without sacrificing the quality and integrity of the connection. The connectors are suitable for a wide range of applications and are supporting millions of products. Additionally, silicone rubber has superior physical and chemical characteristics that enable it to withstand harsh conditions. The elastomeric connectors solderless connection and inherent vibration damping characteristics ensures high performance under vibrations and mechanical shocks.

For portable and handheld devices, the elastomeric connectors offer many benefits over mechanical stacking connectors due to their design flexibility and ability to adapt to tight spaces. In these applications, it is difficult to work with mechanical stacking connectors due to various design constraints. Also, mechanical connectors, may not withstand vibrations and shocks in such applications.

Other benefits include:

  • Other benefits include;
  • Highly flexible hence the ability to bend under pressure without deforming, cracking, or breaking. This makes them suitable for various applications including those where there is vibration.
  • Solderless connection eliminates the risk of solder point break and other solder related failures.
  • The connectors are easy to be customized to provide an interconnection solution which fit a specific application without costly and long customization process.
  • The alternating layers of conducting and insulating materials allow the connector to make multiple points of contact within a very small area, hence saving space. Additionally, if one conductive path fails, the remaining conductive paths will ensure a connection is made..
  • Low insertion force, easy to install, and cost-effective.
  • Highly reliable with the ability to withstand vibrations, shocks, pressure, and stress.

Customizing connectors

Some applications may require special connectors beyond the standard types in the market. Manufacturers are providing a wide range of board-to-board connectors to solve various interconnection challenges. However, most of the manufacturers do not offer customization, and many interconnection solutions are a compromise as this is what is available on the shelve.

Elastomer connectors technology offers flexible and easy to customize solutions which delivers tailor made interconnection solutions and able to work as good replacements for various obsolete connectors.

The cost-effective elastomeric connectors enable manufacturers and technology integrators with cost-effective solutions that help to reduce production costs and complexities. Z-Axis Europe designs and builds cost-effective, custom board-to-board connectors for almost any electronics assembly.

Feel free to contact us for a consultation, additional information and a custom quote.

Traditional custom connectors may present challenges when upgrading or there is a problem that requires a replacement. Although these are used in rugged and highly reliable boards, the maintenance or upgrade of such systems can be difficult. However, the design and flexibility of the elastomeric connectors make them suitable replacements for obsolete and hard-to-find connectors.


Most of today's electronic equipment manufacturers focus on reducing weight, size, and manufacturing costs, and using multiple boards in a small space is one way of achieving the objective. Towards this, a large number of today’s electronic assemblies comprise densely packed printed circuit boards in smaller packages than traditional equivalents. To maximize space, the multi-PCB assemblies may use several printed circuit boards in parallel, perpendicular, or any other required angle, hence fitting more functionality into a smaller space.

Board-to-board connectors help to save space and increase flexibility while giving manufacturers various design and enhancement opportunities. In some medical, industrial computing, and other applications, a single board is not adequate or may only be able to support a handful of functionalities.

However, using the board-to-board connectors makes it possible to have add-on cards that can provide additional functions. In some applications, one connector may support both power and signals. The mixed signal-power connectors eliminate additional connectors while simplifying the design and saving space.

Elastomeric board to board connectors technology is a proven alternative for traditional mechanical connectors with superior performance and low development costs.