Analysis of SAR ADC Performance Under Radiation Exposure

This paper investigates the radiation effects on Successive Approximation Register (SAR) Analog-to-Digital Converters (ADCs) for space applications. Total Ionizing Dose (TID) and Single Event Transient (SET) are considered for two types of SAR ADCs: split capacitor array Digital-to-Analog Converter (DAC) based and C-2C ladder-based DAC based. The effect of TID is modeled as the offset change in the comparator, while the SET effect is simulated through applying instant currents to different nodes on the DACs. According to the simulation results, TID causes missing codes, whereas SET may cause bit flips in the output code depending on the incident time and the location of the SET event. Also, it is observed that the SET performance of the SAR ADC with split capacitor array DAC is better with respect to the C-2C ladder-based DAC. The performed analysis provides valuable circuit design insights to achieve radiation-hardened SAR ADCs.