Quentin: an Ultra-Low-Power PULPissimo SoC in 22nm FDX

The End-Nodes of the Internet of Things (IoT) require extreme energy efficiency coupled with wide power-performance operating range. Fully-depleted SOI (FD-SOI) is an attractive technology for ultra-low power and wide-range operation as it offers compelling options to tune power, performance, area (PPA) at design time as well as at run time. This paper describes Quentin: an MCU-class (32bit) open-source RISC-V SoC featuring an autonomous I/O subsystem optimized to deal with the wide variety of sensors available in IoT end-nodes, coupled with a processor optimized for near threshold computation and a heterogeneous (standard-cell and SRAM) memory architecture to better exploit the low-voltage capabilities of 22nm FDX technology. The system runs up to 2400 million equivalent RV32IMC instructions per second (MOPS) and achieves best power density of 6 μW/MHz, resulting into an energy efficiency of 433 MOPS/mW.