Board-to-Board Connectors

Pin Headers

Pin headers (male) and female headers (socket) are used as a set. A male pin header consists of one or more rows of metal pins molded into a plastic base. Due to their simplicity, male pin headers are the most cost-effective.

PCB orientation is the relative position of two PCBs to be connected by BTB connectors. Here are some of the common orientations of BTB connectors:

In order to cater various PCB orientations (Parallel, Horizontal, Perpendicular), board-to-board connectors have been developed in straight, right angle and U-shaped designs.

Amid the trends of miniaturization, transitioning to light weight and high speed, designers often face many constraints, both mechanically, and electrically. Greenconn offers various solutions to accommodate all stacking options.

Vertical - Parallel, Mezzanine - Both connectors are in a vertical orientation. This allows a PCB to be stacked on top of another, minimizing the surface area as a result.

Horizontal - 180 Degree, Coplanar, Edge-to-Edge - Both connectors are in a horizontal orientation. From the design standpoint, this keeps the mating centerline low profile to the PCBs.

Perpendicular - Motherboard to Daughterboard - Connectors are perpendicular to one another. This is commonly seen in hard drive applications where many "Daughterboards” are stacked onto one motherboard, allowing the data storage space to be efficiently expanded.

Here are some advantages of stacking PCBs: The design can be modularized into smaller PCBs and the PCBs can be connected using BTB connectors later on during assembly. This not only improves the design process but also allows modifications to be made easily.

From the assembly perspective, it can improve the manufacturability of the product, by operating with smaller PCBs rather than one large PCB.

Overall, properly stacking PCBs in layers can enhance the EMC (Electromagnetic Compatibility) of the design.

Connector Pitch is the measurement from the center of one contact to the center of the next contact. When a connector has multiple rows, the pitch in each row and the pitch between rows may be different.

There are numerous factors for the hardware designer to consider when choosing the correct connector pitch:

1. Space Constraints - The smaller the pitch, the smaller the connector can be. In addition, smaller pitch can offer a greater number of contacts within the same space.
2. Electrical Parameter – Pitch size has a positive correlation to electrical specifications such as current rating and dielectric withstanding.
3. Other Physical Constraints - Depending on the design, Greenconn offers numerous low-profile connector options across all pitches. We also accept customization requests.
   

Greenconn’s board-to-board connectors are available in the following rows:

Rows：

Greenconn offers headers and recepticles in single, double, triple, and quadruple row configurations. Single and dual rows are popular choices, while triple and quadruple rows are offered in a smaller number of pitch and style options.

Base Material

Our connectors typically use a copper alloy as the base material for their contacts (pins). However, different alloy materials offer various levels of conductivity performance and physical endurance.

Here’s a comparison of the common base materials offered at Greenconn:

Brass
• Lowest cost
• Good strength and spring properties
• Good conductor

Phosphor Bronze
• High level of strength and conductivity
• Superior elasticity
• Excellent fatigue resistance

Berylium Copper (Be-Cu)
• High level of strength and conductivity
• Highly expansive

Plating

Plating affects the connector’s performance, life cycle, quality, and cost.

Plating involves two parts: underplating and finish plating:

Under-plating

Underplating is used to enhance the performance. This process forms an internal diffusion barrier (Zn and Cu through gold) and prevents pollutants from reacting with base metals. It also acts as a medium to help the finish plating adhere to the base material. Nickel is the most common and important under-plate in current use for these reasons:

• Corrosion resistance
• Wear resistance
• Solderability

Finish plating

Finish plating is the second step of the plating process that helps strengthen the electrical conductivity. There are various options for finish plating, depending on the design requirements and budget.

I. Gold Plating:

• Excellent resistance to corrosion
• Excellent conductivity and low electrical resistance
• High cost

II. Tin Plating:

• Excellent solderability and conductivity
• Low durability and can form an oxide film
• High cost

*Tin can be further characterized as bright tin or matte tin.

A. Bright Tin

Bright tin can be easily identified by its glossy texture. It works well against corrosion, while sacrificing its solderability.

B. Matte Tin

Matte tin, as opposed to bright tin, has a dull texture, which is not as appealing as the bright tin. However, it offers a good level of protection against corrosion without sacrificing its solderability.

III. Selective Gold-Tin Plating

This type of plating offers tin plating on the tail and gold plating on the contact area. It offers a good balance between the advantages of gold and the lower cost of tin.

IV. Others

Greenconn also offers more than just the standard gold and tin plating options. For more information on plating, please contact us as https://www.Greenconn.com/en/contact.htm .