True Random Number Generator with a Metastability-Based Quality Control

A proposed metastability-based true random number generator (TRNG) achieves high entropy and passes NIST randomness test by grading the randomness of each metastable event through the measurement of its resolution time, regardless of the output bit value. This allows the system to determine the original noise level at the time of metastability and to tune itself for maximum randomness. A fully integrated 0.036mm² TRNG is fabricated and measured in a 0.13mum technology.