6 A 40-to-80MHz Sub-4μW/MHz ULV Cortex-M0 MCU SoC in 28nm FDSOI With Dual-Loop Adaptive Back-Bias Generator for 20μs Wake-Up From Deep Fully Retentive Sleep Mode

Near-threshold circuits operating at ultra-low voltage (ULV) have matured with integration in commercial products, such as ultra-low-power (ULP) MCUs for the IoT 1. In this market, MCU design faces the key performance tradeoff between speed, active power, deep-sleep retention power and wakeup time, with the challenge of preserving it over PVT corners. We present a ULP MCU SoC in 28nm FDSOI codenamed SleepRunner, exploiting back-biasing (BB) capability of FDSOI to push the performance tradeoff beyond the state-of-the-art.