ST Releases Flagship Low-Power MCUs and New Process Technology

March 21, 2024 by Jake Hertz

ST made back-to-back announcements on new microcontroller technologies: first, an entry-level, ultra-low-power MCU, and second, a process technology that breaks the 20-nm barrier.

STMicroelectronics is widely considered an industry leader in microcontroller technology. Recently, the company released a new flagship class of ultra-low-power MCUs and advances in the process node of its upcoming MCU offerings.


STM32U0 MCU family

The low-power nature of the STM32U0 MCU family may reduce frequent battery replacements, minimize the number of discarded batteries, and enable more battery-free designs that instead use energy-harvesting systems. 

In this piece, we’ll examine both announcements to see what they bring to the table and how ST is differentiating itself from the competition. 


ST Announces New Ultra-Low-Power MCUs

ST's new STM32U0 MCU family is built around an efficient 32-bit Arm Cortex-M0+ core and can operate at a frequency of up to 56 MHz. Another notable architectural feature (datasheet linked) is the adaptive real-time memory accelerator (ART accelerator) that leverages a 1-KB instruction cache to enable 0-wait state execution from Flash memory. This computing architecture is supported by up to 64 KB of Flash memory and 12 KB of SRAM.


STM32U0 block diagram

STM32U0 block diagram. (Click to enlarge—page 6 of the datasheet.)

Key to the STM32U0's design is its energy efficiency, featuring several power-saving modes like stop, standby, and shutdown modes, which significantly reduce power consumption during idle phases. For example, the device consumes 130 nA of current in VBAT mode, 16 nA in shutdown mode, and 52 uA/MHz in run mode. Based on performance benchmarks of the new family, ST claims a score of 134 CoreMark (2.4 CoreMark/MHz at 56 MHz) and 1.13 DMIPS/MHz (Drystone 2.1).

For connectivity, the STM32U0 series includes various communication interfaces, such as USARTs/LPUARTs, I2Cs, and SPIs, providing ample options for serial communication. The series also features rich analog peripherals, including a 12-bit ADC with 0.4 us conversion time, a 12-bit DAC, a general-purpose op amp, and an ultra-low-power comparator. The MCUs also incorporate advanced security features, including hardware-based read-out protection, secure boot, five passive anti-tamper pins, and customer-code protection. 

ST envisions this new MCU family finding use in IoT deployments, smart sensors, and consumer electronics.


ST Breaks the 20-nm Barrier

In a separate announcement, ST also recently revealed that its upcoming microcontroller family has broken the 20-nm barrier

Leveraging an 18 nm fully depleted silicon-on-insulator (FD-SOI) process augmented with embedded phase-change memory (ePCM), the new microcontrollers promise a remarkable leap in performance and power efficiency. Developed in collaboration with Samsung Foundry, this technology enables larger memory capacities and enhanced integration of analog and digital peripherals.




Key highlights of this technological breakthrough include a 50% improvement in the performance-to-power ratio compared to existing 40-nm embedded non-volatile memory (eNVM) technology. The integration of ePCM facilitates a 2.5-fold increase in non-volatile memory (NVM) density, allowing for larger on-chip memories. Additionally, it yields a threefold enhancement in digital density, accommodating the integration of advanced features such as AI and graphics accelerators, along with security protocols.

The technology can also operate at 3 V, facilitating analog functionalities crucial for power management, reset systems, clock sources, and digital/analog converters. Moreover, the sub-20-nm technology boasts robustness suitable for demanding industrial and automotive applications, with proven reliability in high-temperature environments, radiation resistance, and data retention.


ST Holds Its Ground in MCU Innovation

With two noteworthy announcements in the past month, STMicroelectronics is further solidifying itself as a leader in the microcontroller marketplace. With a new flagship offering in the ultra-low-power space and technological advances in transistor process nodes, ST is pushing the boundaries of its technology so that engineers can have more efficient and performant MCUs.

While the STM32U0 series is now in production, ST will not begin sampling its new sub-20-nm MCUs until the second half of 2024.



All images used courtesy of STMicroelectronics.