We’ve previously seen Ambiq Micro offering Apollo ARM Cortex M4F MCU with Cortex M0+ energy efficiency, and later the upgraded Apollo 2 MCU with even lower power consumption and better performance. The company can achieve such efficiency thanks to low sub-thresold operating voltage in the 0 to 0.5V range. Another startup – Eta Compute – is now offering another low voltage solution with their EtaCore ARM Cortex M3 IP, and other IP blocks operating at low voltage (0.25 to 1.2V).
Eta Compute claims a “10x improvement in power efficiency over any alternative”, and battery life of over 10 years on a CR2032 coin cell. Their website does not provide that many details about the core and development tools, but still mentions the following:
- The only commercially available self-timed technology supporting dynamic voltage scaling (DVS) that is insensitive to process variations, inaccurate device models, and path delay variations
- Includes M0+ and M3 ARM cores scaling 0.3 to 1.2 volt operation with additional low voltage logic support functions such as RTC, AES, and DSP
- Analog to Digital Converter (ADC) sensor interface consuming less than 5uW for the most power constrained applications
- Efficient power management device that supports dynamic voltage scaling down to 0.25V with greater than 80% efficiency
- Encryption and Decryption, signal processing, and real time clocks are other examples of Eta Compute IP supported by DVS, Eta Compute’s technology can be implemented in any standard foundry process with no modifications to the process. This allows ease of adoption of any IP and delivers robust, process and delay insensitive operation. The company’s IP is portable to technology nodes at any foundry simplifying the manufacturing process.
Eta Compute further explains that they developed delay insensitive asynchronous logic (DIAL) design IP for maximum power efficiency allowing small batteries and energy harvesting – such as solar, thermal, vibration, or RF energy harvesting- to power the design.
The company does not appear to make MCU themselves, but they provide EtaCore IP for other companies to design and manufacture MCU based on their solutions. To allow for an evaluation of their solutions, they designed EtaCore ARM Cortex M3 reference design which includes sensors for ambient light, temperature, humidity and pressure, is powered by a half-inch square solar cell, and optionally support LoRaWAN components. The reference design measures 8.9 x 3.8 cm, and can be programmed with Eclipse, Keil and Linux debug and development environments.