Reducing Soft Error Rate of SoCs Analog-to-Digital Interfaces with Design Diversity Redundancy

In this article, a commercial programmable system-on-chip (PSoC 5, from Cypress Semiconductor) is tested under heavy-ion irradiation with a focus on the analog-to-digital interface blocks of the system. For this purpose, a data acquisition system (DAS) was programmed into the device under test and protected with a design diversity redundancy technique. This technique implements different levels of diversity (architectural and temporal) by using two different architectures of converters (a $\Sigma \Delta $ converter and two successive approximation register (SAR) converters) operating with distinct sampling rates. The experiment was performed in a vacuum chamber, using a ¹⁶ O ion beam with 36-MeV energy and sufficient penetration into the silicon to produce an effective linear energy transfer (LET) of 5.5 MeV/mg/cm ² at the active region. The average flux was approximately 350 particles/s/cm ² for 246 min. The individual susceptibility of each converter to single-event effects is evaluated, as well as the whole system cross section. Results show that the proposed technique is effective to mitigate errors originating at the converters since 100% of such errors were corrected by using the diversity redundancy technique. Results also show that the processing unit of the system is susceptible to hangs that can be mitigated using watchdog techniques.