Engineer Spotlight

Just Doing His Job, Pioneering Isolation Technology

Baoxing Chen joined Analog Devices in 1997, with a Ph. D. in physics from the University of Michigan and a B. S. in physics from Nanjing University in China. In 2001, Baoxing and his team released the first iCoupler® product, the ADuM1100, an innovative technology that provides an isolation boundary required in many applications, such as medical devices, plasma TVs, hybrid cars, and industrial equipment. The isolation boundary keeps operators and equipment safe from surges of thousands of volts. Within both ADI and the industry, Baoxing is a recognized expert in isolation and integrated magnetic technology and has recruited and mentored an outstanding team. Beyond providing leadership for the isolation group since its inception, Baoxing has also taken on business related responsibilities for product definition, strategic planning, and interaction with lead customers. He has authored over 30 papers for major external publications and holds 50 U.S. patents.

On your ADI technology claim to fame

iCoupler: Fully integrated signal and power isolation. Optocouplers remained the standard for isolation in microelectronic systems, over many years. With rapidly increasing data rates and a corresponding move toward greater miniaturization driven by ever denser and more sophisticated integrated circuits, optocouplers’ larger size and inherent lack of programmability has highlighted their limitations. Optocouplers can’t meet the ever-increasing bandwidth needs for industry communication buses such as RS-485 in the late 1990s. iCoupler digital isolation not only facilitates significantly higher data rates, but enables miniaturization and digital programmability. iCoupler digital isolation sees speeds increase by more than one order of magnitude while the power consumption sees reductions of over two orders of magnitude. Another critical limitation of optocoupler technology relates to its reliability and long-term robustness. For an optocoupler, its current transfer ratio (CTR) degrades noticeably over time. iCoupler digital isolators, on the other hand, rely on solid-state magnetic coupling, which results in no signal degradation over time, thereby guaranteeing signal and data integrity.

In many applications that require signals and data to be isolated, there is usually a need to also isolate the power. Power isolation is traditionally enabled through the deployment of bulky isolated DC/DC converters. These DC/DC converters are constructed using discrete transformers and diodes. iCoupler digital isolators provide combined signal/data and power isolation in one small IC type device—thus replacing standalone optocouplers and DC/DC converters, which contributes to significant area and size reduction. ADI iCoupler digital isolators revolutionized the isolation industry, essentially transitioning the isolation function from a discrete, bulky, and expensive mechanical-based solution to a modern semiconductor based one. ADI changed the industry and maintains leadership in isolation in the increasingly sophisticated and integrated world of modern microelectronics.

On how it improves people’s lives

With compelling benefits over traditional discrete isolation solutions, iCoupler digital isolation has been adopted into a wide range of applications including industrial automation, instrumentation, motor control, power supplies, energy generation and storage, and more. With >3.5 billion channels shipped, ADI is the leader in digital isolation. A significant and increasing amount of modern medical instrumentation requires isolation to protect the human heart from potentially fatal electric shock in the event of ground faults. Additionally, iCoupler digital isolators enable the development of reliable, compact and easy-to-design patient monitoring equipment. A good example of this is the requirement to have the USB connectivity on ECG equipment enhanced and reinforced with an iCoupler-enabled integrated USB Isolator. iCoupler combines patient safety and video accuracy in medical imaging applications including ultrasound and endoscopy systems. The inherent high speed isolation capability of iCoupler (gigabit isolation) simplifies the construction of very high resolution, with embedded safety, medical imaging systems. Increasingly, these systems must now support the latest >4k displays, which facilitate much faster and increased accuracy of diagnoses.

iCoupler technology also plays an important role in environmental sustainability, especially in the expanding role of electrification in both our transportation and clean energy generation. iCoupler is enabling more efficient solar photovoltaic electricity generation at domestic, commercial and grid level. In electric cars, iCoupler isolated gate drivers not only play a key role in traction inverters, but also enable critical improvements in the car’s battery storage system, which ensures longer time between charges and fast charging and battery storage.

On helping customers stay ahead of what’s possible

iCoupler provides robust and easy to use signal, data and power isolation, simplifying customer system design, guaranteeing safety and data integrity, and reducing time to market for our customers. Its EMC robustness ensures reliable system operation without compromising system performance. iCoupler removes penalties associated with isolation so customers can focus on system optimization without worrying about isolation. It helps them not worry about safety and focus more on changing the future!

On the wow factor about this technology

iCoupler relies on the integration of semiconductor scale microtransformers in working in lock-step with polyimide, an advanced and highly flexible insulation material that is unsurpassed in its ability to provide an isolation barrier and withstand surge voltages up to 20 kV. Unlike all other isolation solutions, iCoupler has the added advantage of isolating power at similar microscopic levels of integration. This means that power as well as data and control signals can all be combined, into a single tiny footprint—a level of integration and miniaturization that’s unsurpassed in the industry. High common mode transient immunity from transformers is yet another capability that allows iCoupler technology to be deployed in applications that have stringent timing requirements in areas such as the driving and control of next generation WBG (wideband gap) power switches including SiC (silicon carbide) and GaN (gallium nitride). Lastly, iCoupler technology leads the way on speed. Its ability to isolate at data rates in excess of one gigabit/sec opens up a vast new array of applications, including high ultra-resolution medical imaging and diagnostics, in a world that is experiencing a rapid expansion in the amount of data and speed with which it needs to be safely and robustly transferred.

On how this technology leverages ADI expertise

As an integrated isolation technology, iCoupler is unsurpassed. Building on ADI’s leadership and expertise in the complete signal chain, we continue to embed iCoupler technology in highly integrated solutions that combine and simplify highly complex signal chains. This includes the integration of iCoupler technology with precision analog-to-digital converters, creating the highest performing and easiest-to-use sensing signal chain for critical applications in energy monitoring and advanced motor control. The integration of ADI iCoupler technology with a vast array of communication transceiver protocols—from RS-485 to CAN USB—not only creates a complete communications PHY, but does so with safety and data integrity built in, providing an easy to use, certified, end-to-end solution.

On working and growing at ADI

While I had solid education with a Ph.D. in physics and an M.S. in E.E., I joined ADI as a fresh graduate, with little knowledge on the market’s needs. I was fortunate enough to work on the right problem, converting an advanced technology lab initiative into a multimillion-dollar business for ADI. This was not possible without the mentorship, teamwork and innovative thinking that is the essence of ADI. This entrepreneurial culture and collaborative spirit not only creates great technology, but nurtures the next generation of talent who will go on to develop even more innovation.

Why stay at ADI … what makes us special?

I stay because of the ability to work on the most challenging problems and to make large societal and business impact. Plus, the chance to work with like-minded and the most innovative and collaborative people anywhere. What makes ADI special is the great engineering culture with engineers working on the hardest problems to be “ahead of what’s possible.” Everyone here understands that innovation is the life blood of the company. ADI leads rather than follows the market. That’s pretty special.

On what you look for in young engineers

Interdisciplinary knowledge and drive to learn. As our customers and their customers look for more complete solutions, we need to broaden our knowledge, beyond circuits to include physics, materials, devices, process, and system at one end and at the other end, engage more deeply with our customers’ and partners’ application end-use cases. We need to have the agility to learn and be successful. There’ll always be challenges, so persistence and dedication are important. ADI has various formal and informal mentoring opportunities. So it’s important we pair senior engineers and young engineers on the same project, so people can learn on the job.

On his passion outside of ADI

Besides reading, I also enjoy watching sports, especially football. I developed my interest in football while at the University of Michigan, a great school with a huge football program. I attended when Tom Brady played there. He’s my favorite player and that fandom continued with the Patriots. I like the Patriots “Do your job” mantra, as it best describes the ADI iCoupler team as well. iCoupler’s success is attributed to many colleagues confidently, quietly doing their job!