A 10 pJ/cycle ultra-low-voltage 32-bit microprocessor system-on-chip

We describe a voltage-scalable 32b microprocessor system-on-chip (SoC) that provides both moderate peak performance (up to 82.5 MHz at 1.2 V) and extreme energy efficiency (10.2 pJ/cycle at 0.54 V) for applications with limited energy budgets and time varying processing loads. The SoC employs low-voltage 8T SRAMs operating down to an array voltage of 0.4 V. Memory access energy is further reduced by miniature (128 B) latch-based instruction and data caches. On chip clock generation and the ability to boot from a small external serial flash ROM makes for a very small overall system.