VITA Standards Benefit Embedded Computing

Military communications applications such as radars, jammers, and super signal interference, use VITA solutions to accommodate a high number of connections in tight density.

VITA (VMEbus International Trade Association) standards promote open system architectures for critical embedded computing with an emphasis on developing those standards in a highly transparent process. Applications embracing these standards often require high reliability and long product life cycles in harsh environments, making stringent specifications an absolute requirement. VITA 67 standards apply specifically to coaxial and RF (radio frequency) interconnects in VPX systems (VITA 46) that integrate high-frequency signals into ruggedized embedded computing systems. Providing VITA 46 VPX board-to-board connections with a standardized coaxial interface for RF makes them ideal for applications that require reliable RF and microwave signal transmission, as well as video and other analog signals.

VITA 67.3 builds on the specifications designed in 67.1 and 67.2 by adding a custom component. Unlike its predecessors, 67.3 doesn’t define the locations of the ports. Floating contacts that had been on the plug-in side, have been moved to the backplane side. These two changes allow designers of plug-in modules to implement direct RF connector PCB launches on the carrier or any mezzanine card, eliminating the requirement for RF cable assemblies, although cable options remain acceptable.

Although using hardware from one OEM is advisable, adherence to the VPX standard makes it possible for hardware from two different OEMs to plug into the same backplane slot.

“When you’re designing for VITA, you usually have two cards and a bunch of signals that have to be transferred between the two cards,” said Jacob Tye, senior mechanical engineer at SV Microwave. “You have a board with a specific amount of space allotted. That space contains several metal blocks. The customer dictates how many ports are needed on each metal block, and each of those ports will be populated with an RF connector. The connector is a little metal cylinder that might have some other special geometry to it, all arranged in a certain pattern that is also dictated by the customer. We then make the mating half, which will be another metal block with the mating connector. It might have cables attached, it might be directly launched to the board, and it will be in whatever envelope the customer specified. The idea is to put as many small connections in this dense space as possible.”

With space at a premium in embedded computing systems, SV Microwave added the Nano VITA 67.3 connector to its VITA 67.3 SMPM and SMPS offerings. Integrating NanoRF modules enhances SV Microwave’s capability to support embedded system designs requiring advanced modular connectivity solutions compliant with both VITA and SOSA standards.

Tye explained that VITA standardizes the locations on the cards, with the idea of fitting in as many signals as possible. “A customer will tell us what VITA spec they want to use and the number of connections they want to make between the two. Then we will design something in that envelope with the number of connections that they asked for. It’s all standardized, so it doesn’t matter who designs it. As long as they know how to design the VITA component to the spec, they will make it happen in that space,” he said. “I work on the subsets of VITA 67, and mainly on 67.3 because that is for custom solutions. If I choose, for example, a rectangular metal block, I can lay out the ports in whatever custom setup I want.”

A lot of what is being developed for military, and other markets, is communication-based technology such as radars, jammers, and super signal interference like electronic optics and infrared. Because they require a lot of connections in tight density, much of the communication and radar-based technology, as well as computer intelligence or surveillance systems, will use VITA solutions because they provide that advantage.

The connector solutions for VITA 67.3 have standard interfaces, but what comes off the connectors can be customized to fit the application requirements. “If the customer wanted to switch to a different kind of cable type, for example, they could use a smaller cable or a larger cable. Also, while the interfaces of the connectors that joined together are going to be the same, the specific design of the connector might differ depending on the applications being used,” Tye said.

Mil-Aero markets are incorporating more VPX embedded computing solutions, increasing the need for full system design prototypes that use ruggedized and specialized cable assemblies. SV Microwave’s line of VITA 67.3 cable assemblies are designed to minimize strain and insertion loss. They are capable of routing signals from the chassis slot to an analyzer and support series VITA NanoRF, SMPM, and SMPS.

Power bricks, also known as the power engines, are the part of the system that provides the actual energy conversion. In an automobile, this would be the equivalent of the internal combustion engine. AirBorn, a Molex company, has been working closely with customers to help them move away from power to VPX card-based solutions that deliver higher power levels without increasing the size or weight of power supplies. “Working alongside a major customer, we developed an intelligent VPX power solution capable of providing more than 2,300 watts of power — nearly double the output of other comparable 6U VPX power supplies,” said Mike Cole, senior vice president and president of Molex’s Aerospace and Defense Solutions Division, who now leads AirBorn. “By AirBorn developing our own power engine, we have the ability to optimize the design to maximize performance while not relying on standard cookie cutter COTS.”  COTS (commercial off-the-shelf components) power bricks are designed to meet many, but not all, basic requirements for numerous system designs, so there are always drawbacks. Developing a discrete power engine design allows system parameters and responses to be customized for integration into the customer’s architecture, with few exceptions, Cole said.

AirBorn, a Molex company, released VPX Power Supply, which offers more than 2,300 watts of power (nearly double the output compared to other 6U VPX power supplies). The series is VITA 62, Open VPX and SOSA compliant and meets MIL-STD 704F and MIL-STD-461G standards.

The power engines can be packaged into many different form factors for many different applications, including VITA 62 form factor (and SOSA/MOSA aligned requirements). “There is tremendous pressure from the U.S. government to standardize into common form factors with the goal of eliminating expensive and long design cycle bespoke designs,” said Cole.

A note about signal integrity

The goal in these applications is to fit as many connections in a designated space as possible. However, with the ports in such high density, noise or crosstalk (a type of electromagnetic interference) can become a problem. Signal density, therefore, factors into the design. The standards ensure that connections and wires aren’t so close together that crosstalk occurs. “You want to space things as densely as possible, but you also don’t want to go overboard and design things in a way where you know you’ll see issues. You want to make sure that the solution is still solid. You have to be very careful about that,” said Tye.

Connector suppliers shape VITA standards

VITA, recognized around the world as a premier standards development organization, provides its members with the ability to develop and promote open technology standards. VITA members who are suppliers with common technology interests can focus on the promotion of specific technologies. SV Microwave has employees who sit on the committee for VITA 67. The committee or the initial drafters can make amendments to the spec, and the committee oversees the documentation associated with those amendments. SV Microwave provides illustrations, as well as some of the actual requirements and guidelines for the standard in terms of trying to position blocks and how to dimension the modules so that they will always be standardized. AirBorn has been a member of VITA for many years and Molex recently participated in Embedded Tech Trends, a VITA-sponsored industry-wide forum where suppliers of component, board, and system level solutions meet with members of relevant industry media to discuss technologies, trends, and products.

To learn more about the companies mentioned in this article, visit the Preferred Supplier pages for SV Microwave and Molex.

Like this article? Check out our other High Density, High-Reliability articles, our Military and Aerospace Market Page and our 2024 and 2025 Article Archives.

Subscribe to our weekly e-newsletters, follow us on LinkedIn, Twitter, and Facebook, and check out our eBook archives for more applicable, expert-informed connectivity content.