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The Smallest Arm Cortex-M4 Microcontroller in the World!

April 21, 2021

By: Carlos A. Rodriguez
Blogger, Maxim Integrated


Since 2017, I've had the pleasure to work with one of Maxim Integrated's most unique microcontrollers, the MAX32660. With 256kB of Flash, 96kB of SRAM, a high-speed Arm-Cortex M4 with FPU, ultra-low power consumption at 50µA/MHZ in active power and optional bootloaders, this MCU packs a ton of capability into a ridiculously small form factor. Its most popular packages are a 3mm x 3mm TQFN and an incredible 1.6mm x 1.6mm WLP…crazy, I know. This makes it the world's smallest cortex-M4F powered microcontroller able to go into applications that are pushing the envelope and bringing complex algorithms into space constrained environments like never before.

When we first launched this microcontroller, the intention was always to have an IC that could help encapsulate our own Maxim Integrated health algorithms (e.g. MAX32664) and to create a place to store companies' proprietary firmware and IP. This resulted in a miniscule but powerful microcontroller that can serve as a sensor hub for all sorts of applications. Allowing the host microcontroller to free up to perform more demanding tasks like wireless communication & data management, or simply to allow the host to be asleep and ultimately save system power. All the features and specifications were built around this idea, and as of today it is safe to say that it has been a success.


MAX32660 Arm Cortex M4 Microcontroller with Embedded Algorithms

With this in mind, there's a couple of ways customers can make the most out of the MAX32660:

  • The first option is to design-in using the MAX32660GWE+T without any preloaded bootloaders giving the freedom to develop an individual bootloader with the specific requirements for the customer's application.
  • The second option is using the MAX32660GWEBL+T which comes preprogrammed with Maxim Integrated's non-secure bootloader. This bootloader allows communication through SPI, I2C & UART and facilitates over the air (OTA) updates on the firmware after products have been deployed to the field.
  • The last option, but certainly not the least, is using a custom version, like the MAX32663A, where Maxim Integrated collaborates with a third-party algorithm provider to securely store their algorithms into the device via Maxim Integrated's proprietary secured bootloader.

All of these are excellent options depending on your application. That said, let's dig in a bit into what Maxim Integrated has done with the MAX32663A to provide more insight on this last option…The MAX32663A in simple terms is a MAX32660 microcontroller, which protects firmware and ECG algorithms through a highly secure bootloader. The firmware itself allows seamless communication with Maxim's MAX30003 ECG AFE sensor, while the algorithms do all the interpretation of the ECG signals coming from the AFE. These algorithms are proprietary IP of Maxim Integrated's partner, B-Secur. B-Secur has plenty of in-depth experience with ECG signals. They're differentiating themselves by providing unique features in their algorithms like measuring heart rate variability, stress levels, identifying/authenticating users via their personal ECG waveform and more recently detection of heart arrythmias like tachycardia, bradycardia and A-Fib. (note: this last feature will be added to the MAX32663A sensor hub in the near future)

Now, I also want to highlight that this same model was used in the MAX32664 which encapsulates Maxim Integrated's own PPG algorithms to measure all sort of things including SpO2, Blood Pressure, HRV, HR and other very interesting measurements. It simply demonstrates how confident Maxim is in its security features.

This particular business model for selling algorithms allows future partners to have great advantages, a few of which are listed below:

  1. Reduces costs & lead times by avoiding algorithm development costs and integration of hardware (AFE + Host MCU + Sensor Hub).
  2. Avoids algorithm licensing by delivering inside a sensor hub.
  3. Minimizes overall power consumption by running algorithms in an ultra-low power microcontroller.

In conclusion, the MAX32660 is an exceptional vehicle for encapsulating and protecting all types of algorithms by providing the least obtrusive platform in the market.

For more information check out our product pages below…