Research On PUF Based On Capacitance Mismatch In SAR ADC

Wireless Sensor Network(WSN)is widely used nowadays,which requires the use of successive approximation analog-to-digital converters(SAR ADCs)to process external analog signals,however,WSNs are vulnerable to attacks when performing signal processing.This paper proposes a physical unclonable function(PUF)based on capacitor mismatch in SAR ADC to provide security for the system without affecting WSN data processing and consuming excess hardware resources.In this paper,PUFs based on capacitive mismatch in SAR ADCs are investigated in the following work.1.A low-power charge redistribution SAR ADC based on SMIC 55 nm CMOS process is proposed: the power consumption of SAR ADC is reduced by optimizing its capacitor array successive approximation conversion scheme;a new gate voltage bootstrap sampling switch circuit is adopted,resulting in improved sampling switch linearity;the structure of the dynamic latching comparator is optimized and adjusted to reduce the impact of comparator noise and detuning and other problems on the circuit;the digital SAR logic adopts synchronous control to reduce the power consumption of the register set in the control logic by making the D flip-flop self-locking at the right time.2.The working principle of SAR ADC and PUF based on capacitive mismatch is analyzed,and the theoretical basis and working principle of PUF based on capacitive mismatch in SAR ADC are given.Then the capacitance mismatch based PUF is implemented on the basis of the designed low power SAR ADC and extensive Monte Carlo simulations are performed for this PUF.The overall simulation of SAR ADC circuit by cadence's spectre,under the condition of sampling frequency of 1MHz and input signal frequency of 16.601 k Hz,the SFDR of the SAR ADC designed in this paper is 73.6d B and the ENOB is 9.81 bits.The average power consumption of the overall circuit at the global supply voltage VDD of 1.2V is 1.4u W,and the FOM value is 1.55 f J/conversion-step.The average inter-chip Hamming distance of the proposed PUF is 0.48 and the average intra-chip Hamming distance is 0.01,indicating that the PUF has good stability and uniqueness.In addition,a large amount of simulation data shows that the uniformity of PUF response output also performs well and meets the security requirements of wireless sensor networks.