“When selecting connectors, electrical interconnect performance such as transmission rate, current that can be carried, and voltage must be the factors that developers are very concerned about. In addition, the reliability and durability of connectors are often a priority. elements. This is easy to understand – if a connector is just a “flower in a greenhouse” that cannot withstand the ups and downs of the real application environment, then its nominal performance parameters are useless.
When selecting connectors, electrical interconnect performance such as transmission rate, current that can be carried, and voltage must be the factors that developers are very concerned about. In addition, the reliability and durability of connectors are often a priority. elements. This is easy to understand – if a connector is just a “flower in a greenhouse” that cannot withstand the ups and downs of the real application environment, then its nominal performance parameters are useless.
Therefore, continuously enhancing the product’s tolerance to harsh environments has always been an important direction for connector manufacturers’ technological iteration, and it is also an important indicator of their own product differentiation. As a result, the Rugged Connector has gradually developed into an important product line.
Features of Durable Connectors
The so-called “durable” may be understood differently by different people, but “durable” connectors usually include the following features:
• Maintains mechanical and electrical integrity after exposure to harsh environments and multiple mating operations;
• Can withstand high mechanical shock and vibration without affecting interconnect performance;
• Can provide good EMI shielding characteristics in complex electromagnetic environment.
In order to improve durability, modern connector products are usually optimized through the following aspects:
Mainly make a fuss about the contact material, coating and structure, from reducing the contact resistance of the contact, increasing the area of the contact area, enhancing the normal force of the mating, reducing the environmental exposure and the mechanical strength deterioration after repeated mating, etc. aspects are optimized.
On the one hand, the insulating material must meet the requirements of the design specifications, and on the other hand, the structure of the entire insulator must also form a comprehensive protection for the contacts, so as to avoid the influence of external factors on the contacts as much as possible.
Locking and Termination
The additional latch mechanism helps the mated connector to cope with higher mechanical shocks and vibrations. At the same time, in terms of termination to the PCB, fastening methods such as screws, soldering, and soldering nails are also provided to meet high durability. sex, stability.
Sealing and Shielding
Specialized seals and shields are naturally indispensable for connectors that require protection against water, dust, and electromagnetic interference.
Around these aspects, the major connector manufacturers are also the Eight Immortals crossing the sea, showing their abilities and practicing their own unique skills in the market. Among them, when it comes to Samtec’s durable connector products, its stunts in “contact” design can be regarded as outstanding.
Unique Tiger Eye™contact system
Tiger Eye™The contact system is one of Samtec’s masterpieces, designed for miniature durable, high reliability, high mating cycles, rated for over 1,000 mating cycles.
Figure 1: Tiger Eye contact system (Image credit: Samtec)
The Tiger Eye system has carefully considered the selection of contact materials. It is known that common materials available for contact substrates include brass, phosphor bronze and beryllium copper (BeCu). Among them, brass is a very cheap one of the three metal materials. It has excellent electrical properties, but due to its low yield strength, it is not suitable for contact beams in sockets. Phosphor bronze is stronger and more resilient than brass, making it suitable for applications where contact mating cycles and flexure are not critical. The Tiger Eye contact system uses a third material, a heat-treated beryllium copper alloy. Although this material is more expensive, the resulting contacts are very mechanically resilient and, once formed and hardened, retain their shape under a variety of conditions, providing not only higher mechanical strength and electrical performance, but also for It is also beneficial to improve the high reliability and high durability of the product, which can be said to be an ideal “candidate” for harsh environments and high mating cycles.
The Tiger Eye system is also ingenious in the design of the contact mechanism. It adopts a “multi-finger” structure, and the contact mating surface is located on the flat and smooth side of each “gold finger”. The smooth surface can prolong the plugging life of the connector as much as possible, and also reduce the pressure on the electroplating process. , the contact resistance is also lower.
There is also a very clever “detail” on the Tiger Eye contacts – a micro-groove is designed on the tail, which allows the solder paste to penetrate the groove during reflow soldering, wetting the larger surface area on the lead to provide greater soldering point strength; at the same time, compared with ordinary flat leads, this connector with tail microgrooves can better adhere to wet solder paste, these characteristics all help to improve the mechanical strength of the connector assembly on the PCB.
In addition, the Tiger Eye contacts also have a micro-groove in the transition area between the gull wing tail and the contacts, which acts to prevent the “wicking” effect of the solder. Although the amount of solder in the SMT process is relatively small, the “wick” effect is not common, but once it occurs, this micro-groove can destroy the capillary action and prevent the solder from migrating to the contact contact area and affecting the connection performance.
It can be said that the Tiger Eye contact system strives to be in place in every detail, which also provides a solid foundation for creating durable connector products with excellent performance based on the Tiger Eye contact system.
Figure 2: Key features of the Tiger Eye contact system (Image credit: Samtec)
Based on Tiger Eye™board-to-board connectors
At present, Samtec has developed products with three pitches (0.80mm, 1.27mm and 2.00mm) based on the Tiger Eye contact system. Among them, the TFM/SFM series pin/header board-to-board connectors with 1.27mm contact pitch are the widest Products favored by users of interconnect solutions in industrial and other harsh environments.
Figure 3: TFM/SFM series pin/header board-to-board connectors (Image source: Samtec)
Among them, the TFM 1.27mm pin connector has a shield shell, and the polarized design can realize blind mating. It has a cylindrical terminal with a diameter of 0.018″ (0.46mm), and the single-row and double-row layout can support 100 pins; the Available in a variety of options such as screw fastening, solder tabs and solder studs, the series can meet the needs of most high-durability application scenarios, and can provide vertical, right-angle, horizontal mounting methods, as well as through-hole, surface mount different end connected products.
Figure 4: TFM series pin board-to-board connectors (Image source: Samtec)
The SFM series 1.27mm headers used to mate with the TFM series pins are also available in polarized single-row and double-row layouts, up to 100 pins, and screw-on and solder-nail options are also available to meet high durability requirements . Its vertical and horizontal mounting orientations, through-hole and surface-mount terminations, also allow for greater application flexibility.
Figure 5: SFM series header board-to-board connectors (Image source: Samtec)
With the support of Tiger Eye contact system, one of the highlights of TFM/SFM series board-to-board connectors is of course reliability and durability – these connector products have passed Samtec’s extremely stringent SET test (strict environmental testing).
You must know that SET is a set of test standards “customized” by Samtec to measure the ability of connectors to withstand harsh environments, including the standard Design Qualification Testing (DQT) and Extended Life Product previously introduced by Samtec.™(ELP™) tests, with some additional tests for interconnected system applications in more extreme/harsh applications or environments, beyond what is required by typical industry standards. Therefore, it can be said that a product that has passed the SET test and obtained the following mark means that it is already the “top class” in durable connectors.
Figure 6: Samtec Severe Environment Testing (SET) logo (Credit: Samtec)
Just how “durable” the TFM/SFM series connectors tested by SET are, you can see at a glance through the following set of product specification data:
Durability Specifications for TFM/SFM Series Connectors
• Number of insertion and removal cycles at 100% relative humidity: 250 times
• Simulated 70,000 feet high-altitude electric strength (DWV): Voltage 300VACfor 60 seconds without breakdown
• Electrostatic discharge (ESD) test voltage: 5kV, 10kV, 15kV
• 500 temperature cycles: temperature range -65°C to +125°C, dwell time 30 minutes
• Mechanical shock: peak 40G, duration 11ms, half-sine waveform
• Random vibration: 12gRMS, frequency 5Hz to 2,000Hz, 1 hour duration per axis
Obviously, you can rest assured that such products are used in the military/aviation industry, as well as in the automotive, industrial and medical fields.
Summary of this article
Faster transmission speed, greater transmission power, more compact product size, higher ferrule density… These are the main tracks in the connector product competition. On this basis, if anyone’s products can be unique in reliability and durability, they can further gain a differentiated competitive advantage and win an important position in some specific application fields.
Samtec’s TFM/SFM 1.27mm series board-to-board connectors, based on the Tiger Eye contact system designed for rugged applications, provide users with an ideal solution for high-reliability, high-durability interconnect applications, and It also maintains excellent electrical performance and a slender “stature”. If you want to learn more about these “little men” who are not afraid of harsh environments, please visit the product page on the Mouser Electronics website!
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