A 65nm 25MHz ultra-low-voltage microcontroller SoC is implemented with an embedded all-digital adaptive voltage scaling system, a glitch-masking instruction cache with no miss latency and a robust clock tree for low-voltage timing closure. It achieves 7µW/MHz power consumption in active mode, 1.5µW sleep power and 0.66mm² area to save on carbon footprint of sensor nodes.
Bol, D., De Vos, J., Hocquet, C., Durvaux, F., Botman, F., Boyd, S., Flandre, D., & Legat, J.-D. (2012). A 25MHz 7μW/MHz Ultra-Low-Voltage Microcontroller SoC in 65nm LP/GP CMOS for Low-Carbon Wireless Sensor Nodes. IEEE International Solid State Circuits Conference. Digest of Technical Papers, 55(1), 490-491. https://doi.org/10.1109/ISSCC.2012.6177104 (Original work published 2012)