A Single-Inverter-Based True Random Number Generator with On-Chip Clock-Tuning-Based Entropy Calibration Circuit

Abstract

This paper introduces an inverter-based true random number generator (I-TRNG). It uses a single CMOS inverter to amplify thermal noise multiple times. An adaptive calibration mechanism based on clock tuning provides robust operation across a wide range of supply voltage 0.5~1.1 V and temperature −40~140 • C. An 8-bit Von-Neumann postprocessing circuit (VN8W) is implemented for maximum raw entropy extraction. In a 130 nm CMOS technology, the I-TRNG entropy source only occupies 635 µm 2 and consumes 0.016 pJ/raw-bit at 0.6 V. The I-TRNG occupies 13406 µm 2 , including the entropy source, adaptive calibration circuit, and post-processing circuit. The minimum energy consumption of the I-TRNG is 1.38 pJ/bit at 0.5 V, while passing all NIST 800-22 and 800-90B tests. Moreover, an equivalent 15-year life at 0.7 V, 25 • C is confirmed by an accelerated NBTI aging test.