Tiny Size Brings Big Challenges: The Inside Story of XIAO ESP32S3 Designing – Discover the Hard Work, Passion, and Innovation Behind the Scenes

Both XIAO ESP32S3 and XIAO ESP32S3 Sense are available now!

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The debut of the XIAO ESP32S3 caused a sensation in the community, and we’re thrilled to see so much interest in our latest member of the XIAO Series. We’ve received numerous requests for more information on the specs and functions of this dev board, which has only increased our motivation to deliver a remarkable product. With high standards set, our R&D team is working tirelessly to exceed them. Utilizing cutting-edge technology and coordinating resources, we’re dedicated to delivering another high-quality product that our community can be proud of. The excitement is contagious, and we can’t wait to share with you the story about the XIAO ESP32S3 design. 

Join us to witness what we’ve built today. From a manuscript to an existing powerful microcontroller with high expectations, we invite you to discover the hard work, passion, and dedication that went into making it all possible.

Breakthrough we Made: Incredibly Mini and Compact Board-to-Board Connector with 0.4mm Pin Distance, high Integration Level Parallel to Consumer Electronics, Firstly Achieved in Seeed’s MCUs

The highlighted part by red lines is called a board-to-board connector used to accurately interconnect printed circuit boards (PCBs) in a stackable manner. What we want to emphasize most is its impressively compact size, while still accommodating a whopping 30 pins with an extreme pin distance of just 0.4mm! We have a benchmark to prove how incredible the breakthrough is!  0.8mm is the commonly used distance between the pins in a board-to-board connector for MCUs on the market. We just cut it a half! 

A sense of pride, satisfaction, and accomplishment comes along with this tiny, highly-integrated board-to-board connector since it is: 

• an innovation in XIAO Series, even among the MCUs of Seeed

We never use such tiny size board-to-board connectors in other XIAO Series, even any other boards in XIAO’s MCUs.  XIAO Series is known for its incredibly small form factor. When developing the XIAO ESP32S3, we recognized the critical importance of using micro board-to-board connectors to minimize size and space. By doing so, we were able to pack more functionality into a limited form factor, allowing us to realize its powerful functions of it in a tiny package. It means a lot for us to meet the needs and expectations of customers and ourselves who already demand high-performance capabilities in a compact device. 

• a high degree of Integration level parallel to consumer electronics

Consumer electronics generally have a higher degree of integration compared to pure microcontrollers. Such a high degree of integration requires careful design and engineering, as well as a deep understanding of the various technologies involved. We invest significant resources in R&D just to realize powerful functions in such a limited space. 

Produced by Foxconn’s high-precision machining and advanced surface mount technology (SMT) with a pad spacing of just 0.2mm, a limit value in production!

XIAO ESP32S3 is produced by Foxconn using advanced machining technology. With a pad spacing of just 0.2mm, it is a testament to the precise and accurate assembly and production achieved through state-of-the-art machining techniques.

What Kind of Standards We Set for XIAO ESP32S3’s Production? 

Considering that Foxconn has quite mature experience in SMT, we choose to partner with Foxconn to ensure the high quality of XIAO ESP32S3. By using cutting-edge machining techniques, Foxconn can produce parts with tight tolerances and high dimensional accuracy, ensuring the quality and reliability of its products. It has invested heavily in advanced automation and robotics technology to improve production efficiency and product quality. We can expect XIAO ESP32S3 to have: 

• robust and reliable solder joints: solder joints are strong and durable to withstand the stresses and strains of operation and environmental conditions
• thorough inspection and testing: undergo thorough inspection and testing to ensure they meet design specifications and quality standards

0.2mm Pad Spacing: a limit value, a breakthrough in Microcontroller, a miracle achieved in XIAO ESP32S3

For the processing capability of mainstream PCB manufacturers, the distance between the pads and the pads must not be less than 0.2mm. In other words, 0.2mm is a limit value of pad spacing! How close is 0.2mm? 0.2mm is approximately equal to 0.00787 inches, or 7.87 thousandths of an inch. To give you a sense of scale, 0.2mm is about the width of a standard human hair, so you can imagine it as a very thin, almost imperceptible line. We are quite proud of the breakthrough we achieved in this aspect by utilizing advanced production technology. 

Leverage Seeed’s Agile Manufacturing Resources

Foxconn is a leading electronics manufacturing company with a proven track record of producing high-quality electronic devices at scale. Through partnering with Foxconn, we are able to leverage their cutting-edge production technology. The cooperation with Foxconn embodies Seeed’s agile manufacturing and services. Located in Shenzhen, we are able to take advantage of vast resources, favorable policies, efficient supply chains, and extensive knowledge to produce goods and provide services with unparalleled efficiency. 

Tiny but Powerful: Continually adjusting and Testing to Ensure functional Integrity in Limited Space

When it comes to designing the XIAO ESP32S3, we face a significant challenge – fitting a vast array of essential electronic components within limited space. In order to tackle this obstacle, our R&D team has been diligently researching and testing feasible solutions. Through this process, we have discarded many approaches and continued to explore new ones, all while striving to uphold our commitment to meeting and exceeding the expectations of our customers. More importantly, we need to live up to the highest standards we set ourselves and refuse to compromise on quality. 

Though our engineering team is seasoned, they still look through Power Supply Manual and Design Guideline for Microcontroller to explore possible ways of possible ways to adjust the redundant design and reduce needed area while maintaining functionality and stability. 

Here is a picture to demonstrate 3 redundant capacitors we removed. At the same time, we adjusted other capacitors on VCC_3V3 in order to lower the risks brought by it. 

We have already removed redundant design, yet the space is still unable to accommodate so many components, then we try to replace them with smaller size oscillators, in the meanwhile, keep adjusting capacitors to reduce the risk brought by frequency offset. 

Though we already tried removing redundant design, adjusting the packaging solution for larger components, and minimizing space between components, XIAO ESP32S3 still can not accommodate so many electronic components, therefore, we decide to walk out of our comfort zone and search for smaller components in the market instead of using those we are familiar with. We found a smaller diode we never used before and spend lots of time testing it just in order to ensure its stability and high quality after we adopted it into our solution. 

Thank you all for joining us to witness the challenges we faced and the triumphs we celebrated. We will unveil more details about behind-the-scene stories about Seeed R&D. Don’t miss what happens next!

If you have any problems/feedback about XIAO ESP32S3, or you are curious about specific topics we have not covered yet, free feel to leave comments below and let us know your thoughts!

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