Adaptive Body Bias Aware Implementation for Ultra-Low-Voltage Designs in 22FDX Technology

A 0.5V ultra-low voltage Arm Cortex-M4F MCU in a 22nm FDSOI technology with 512kB SRAM and 140MHz operating frequency with 11.5μW/MHz is presented. An all-digital closed-loop continuous adaptive body biasing with individual P and N compensation and low ripple less than 30mV enables target performance from -40°C to 125°C and over full process corner range. The MCU has been implemented using an adaptive body bias aware implementation flow, which considers the corner tightening during implementation and sign-off for improved power, performance and area.