Circuit Board Connectors Hybrid Connectors for Easier Circuit Board Design

Related Vendor

Wuxi InfiMotion Technology Co., Ltd.

Flexible Board-to-Board connectors save space in circuit board design and increase the data rate. Both requirements can be combined without routing power and signals via separate connectors using the hybrid Zero8 connector.

*Dominik Dotzer is a Product Manager at ept in Peiting/Germany.

In real-world applications, the contacts of a board-to-board connector are generally not constantly loaded with the maximum current value. One reason is the safety margin to ensure the reliability and longevity of the connectors. Thermal management also prevents the developer from running high currents through the contacts, as overheating can occur.

Additional reasons include lifespan, voltage drops and signal quality, as well as a heterogeneous application profile with varying power consumption depending on the operating state. Therefore, the maximum current value of a board-to-board connector is often considered as a limit for extreme conditions.

Normally, only individual contacts are needed for the power supply of an electrical device. The remainder of the contacts ensure signal transmission between two printed circuit boards. The signals are transmitted in the mA range in high-frequency applications, which in turn leads to barely measurable heating of the signal contacts.

When individual pins are powered, laboratory results show that less heat energy is generated, resulting in significantly better current carrying capacity. There is no risk of the connector overheating, and this problem is rather shifted to the circuit board.

Simultaneous power and signal transmission in the connector

With hybrid board-to-board connectors, you only need one connector for power and signals: The prerequisites for this are, on the one hand, the suitable material composition of the insulating body and pins and, on the other hand, the contact geometry with small changes in cross-section. If these criteria are met, both high currents and RF signals can be transmitted with the correct pin assignment in a connector. Tests have shown that it is advisable to use the outer contacts for power transmission and to separate them from the differential pairs for signal transmission via additional ground contacts.

This separation prevents electromagnetic influences of the power transmission on the signal transmission and also achieves better thermal distribution. In addition, the soldering surfaces of the board locks and the shielding plates can be combined with the power contacts and serve as additional heat sinks. If partially equipped connectors are used, the power and signal transmission can be optimized even further.

High speed and current carrying capacity are therefore quite compatible with each other scalable: This variant offers the decisive advantage for the PCB design that additional connectors for power transmission can be dispensed with. Unnecessary costs, for example, due to double material procurement, approval loops and storage can be eliminated as well as the risk factor that arises from lack of tolerance compensation between different connectors. In times of increasing miniaturization, this is another plus point for hardware developers, as they save valuable installation space in their application.

More design flexibility with hybrid connectors

With the Zero8 connector, ept has combined both worlds, as it allows the combination of high currents and high-speed signals in one connector. As a pure data connector, high transmission rates of over 16 GBit are possible and when used as a pure power connector, current transmissions of 1.7 A are possible with 80-pole design and full utilization.

By combining both characteristics and using specifically defined pins for power transmission, even higher currents are possible at a constant transmission rate. In this configuration, significantly higher currents can be achieved per pin, while the remaining pins can still transmit high-speed signals.

In the power test we conducted ourselves, we applied current to only the outer four contacts in a special layout and combined it with a board lock over a solder pad for heat dissipation. All other contacts are used for signal transmission and the result is a current transfer of 7.8 A per pin.

Image 1 provides an example of how different current ratings per contact result from the Zero8 connector depending on the number of poles and the number of current-carrying contacts. One reason for this is the lower formation of hotspots inside connectors with a small number of poles: Here, less heat is generated and this can be better distributed. The heat is dissipated even better when the current is carried over only a small proportion of the contacts.

Depending on the specific requirements in the application - i.e., the design priorities, available space, costs, and required reliability—the decision is made whether to use hybrid or separate connectors. Hybrid connectors offer an efficient solution for compact designs and tight installation spaces.

Regardless of these criteria, all design alternatives are opened up with the board-to-board connectors: Whether PCB distances from 6 to 21 mm or in 12-pin to 80-pin design—with the Zero8 product family, PCBs can also be designed flexibly with regard to shielding, particularly in applications that require reliable high-speed data transfer and good scalability in board-to-board communication.

With the gender-neutral connection technology ScaleX with interlocking blade and spring bars, the connectors can also withstand high vibration and shock—making them suitable for industries that require a reliable, scalable, and efficient connection solution.

This article was first published on our sister brand 'ElektronikPRAXIS' (German Edition), Vogel Communications Group