Menlo Micro claims highest-power MEMS switch

Menlo Micro has claimed the industry’s highest-power MEMS switch with the introduction of the MM9200 with kilowatt-power handling. Based on the company’s Ideal Switch technology, the MM9200 is the first MEMS power switch that is capable of handling 10 A in a 5 × 5-mm WLCSP package.

The power switch touts the lowest loss with an ultra-low 0.010-Ω contact resistance. The device also offers low power consumption, low leakage current and high standoff voltage (±300 V).

Other key features include a fast switching time of 10 μs (open and close) and 1 billion switching operations. The actuation speed is more than 1,000× faster than its electromechanical equivalent, which enables new concepts for power switching and protection, according to the company.

Breaking new ground, the MM9200 integrates more than 400 individual switches to support kilowatts of power in a small surface-mount package, said Chris Giovanniello, co-founder and SVP of marketing at Menlo Micro. The new devices are expected to contribute to increasing the energy efficiency, functionality and reliability in a variety of smart-power and energy-distribution applications.

With a 1,000× longer lifetime than a traditional mechanical relay, and approaching the reliability of semiconductors, the Ideal Switch offers the lifetime of semiconductors with the electrical losses of a mechanical device, Giovanniello said.

The MM9200 is Menlo Micro’s first product in the power market, previously focused on RF switches. The products in production are various RF switching designs, but the new MM9200 offers an unprecedented level of power handling and power density and super-low loss of 10 mΩ of contact resistance, handling 10 A of steady-state current in a small surface-mount device, said Giovanniello.

This is an unprecedented level of power-handling performance in a MEMS switch, delivering “a completely new step in power handling,” he added.

Giovanniello said the core Ideal Switch technology — invented by General Electric — was always intended for power switching in industrial controls. Menlo Micro was spun out of GE in 2016 as a separate company to further the development of MEMS switch technology.

The company started with high-value RF products because it was a little less challenging from an engineering perspective, but it was always the goal to tackle power, which was the original impetus for the invention of the technology, said Giovanniello.

It also is a much larger market opportunity in the longer term because so much of the world of controls and energy distribution is still done mechanically and is ripe for disruption, he said. “The MM9200 is the first step on that journey.”

Giovanniello estimates that about 80% of the market for power relays is still mechanical primarily because of the electrical performance of the metal-to-metal contact, which hasn’t been displaced by solid-state relays for the most part.

Semiconductors are used in cases where there are either reliability or speed concerns because mechanical relays are slow: They don’t switch very fast, and they wear out in a few thousand operations and have to be replaced, he added.

The MEMS switch delivers the best of both mechanical and semiconductor worlds.

“The real benefit is having something extremely small and very low-loss, with the speed and reliability of semiconductor devices and the electrical performance of a mechanical device, which is attractive when handling very large loads and high power,” said Giovanniello.

Like all Menlo Micro Ideal Switch products, the MM9200 uses true metal-to-metal contacts, which reduce losses and power dissipation by more than 90% when compared with solid-state devices. “This design, combined with the Ideal Switch electrostatic drive, makes the MM9200 the most power-efficient and space-efficient high-power switch in the market,” said the company.

Traditional solid-state power relays, which aren’t built with a metal-to-metal conductor, are constantly dissipating heat when pushing a continuous load through them, and to function, they need enormous heat sinks, said Giovanniello. “The higher the power, the bigger the heat sink.”

The MM9200 targets a variety of applications including industrial automation, smart building controls, advanced energy management systems and other space-constrained power-distribution applications from microgrids to smart circuit breakers and smart point-of-load switching. The scalable design and process technology of the Ideal Switch technology enables total management and control in these applications with a “virtually loss-less solution,” said the company.

In addition to the billions of switching cycles, which provides 1,000× better lifetime than traditional electromechanical relays, said Giovanniello, the Ideal Switch technology also offers arc-free capability for higher safety not previously possible for industrial automation applications. Together, these features also can reduce unplanned maintenance and related costs.

More power

Although the process and structure for the RF and power products are the same, the design is different in order to handle the 10 A. The company added some innovations around integration, thermal management and current sharing across a large number of switches to keep the heat down and achieve the high current density.

Although Menlo Micro has settled on 10 A for now, the company is in the process of building next-generation products with higher power density. “You can place multiple MM9200s in parallel to further reduce the resistance and increase the current-carrying capability,” said Giovanniello. “It has the ability to share current across multiple devices to go from 10 A to 20 A to 30 A to 50 A. It’s very scalable in terms of putting more devices in parallel, and you can reduce the resistance and add more current, so that is on our roadmap in the years to come.” Watch the animation to see how it works.

Also on the roadmap are smaller form factors and higher integration, incorporating features like smart sensing, metering and controls, as well as protection. “These devices will provide a lot more intelligence than a traditional relay because we’re able to shrink everything down so small and add a lot of these value-added smart features without paying a penalty in the size,” said Giovanniello.

During a recent demo, the devices were below the company’s targeted resistance of 5 mΩ. At a 1.4-kW load, the temperature rose only about five or six degrees over ambient under those conditions, which means there isn’t a need to have any special technology for cooling if you don’t generate any heat, he said.

The demo also showed practically zero power loss through the MM9200. If it were a solid-state relay that was dissipating under the same load, it would be close to 7 W of waste heat and constantly throwing away efficiency and power through the heat sink, he added.

“There are applications that have high reliability requirements or need faster turn-on and turn-off times and will suffer the penalties of solid-state relays with these large heat sinks,” he said. “We’re bringing to market a better way to do that in a much smaller form factor without any efficiency losses due to semiconductors.”

Menlo Micro is working with early-access customers on the evaluation of the MM9200. Evaluation boards and engineering samples for general sampling will be available in the first half of 2023, followed by production in the second half of 2023.