A 47.14- 200-MHz MOS/MTJ-Hybrid Nonvolatile Microcontroller Unit Embedding STT-MRAM and FPGA for IoT Applications

The demand for energy-efficient, high-performance microcontroller units (MCUs) for the use in power-supply-critical Internet-of-Things (IoT) sensor-node applications has witnessed a substantial increase. In response, research concerning the development of several low-power-consuming MCUs has been actively pursued. The performance level of such MCUs, however, has not been sufficient, thereby rendering them non-feasible for the use in IoT sensor-node applications that process a large number of received signals immediately followed by extraction of valuable information from them to limit data transferred to a data center. To realize next-generation IoT systems based on intelligent sensor-node application, ultra-low-power high-performance MCUs need to be developed. This paper presents an ultra-low-power-consuming and high-performance MCU configuration based on the spintronics device technology, using which all modules are non-volatilized, and any wasteful power consumption is eliminated by controlling the power supplied independently to each module. By incorporating a reconfigurable accelerator module, for performing various signal-processing procedures in sensor-node applications, and a memory controller, which can speed up the entire system by relaxing the data-transfer bottleneck of logic and memory, the proposed MCU configuration achieves ultra-low power consumption and high-speed operation. As confirmed by the results obtained via measurements performed on a fabricated chip, the proposed MCU design, on average, consumed 47.14 μW power at an operating frequency of 200 MHz. This corresponds to the world's highest signal-processing performance and energy efficiency of highly functional IoT sensor nodes powered by harvested energy.