A 82nW chaotic-map true random number generator based on sub-ranging SAR ADC

Abstract

An ultra-low power true random number generator (TRNG) based on sub-ranging SAR ADC is proposed. The proposed TRNG shares the coarse-ADC circuit with sub-ranging SAR ADC for area reduction. The shared coarse-ADC not only plays the role of discrete-time chaotic circuit or TRNG's entropy source but also reduces overall SAR ADC energy consumption by selectively activating the fine-SAR ADC. Also, the proposed dynamic residue amplifier and adaptive-reset comparator generate chaotic map with low power consumption. TRNG core occupies 0.0045mm 2 in 0.18μm CMOS technology and consumes 82nW at 270kbps throughput with 0.6V supply. The proposed TRNG passes all NIST tests and it achieves a state-of-the-art FOM of 0.3pJ/bit.