The Design of Single-Event Hardened Analog and Mixed-Signal Circuits

Abstract

Modern systems-on-chip (SOCs) must incorporate high-performance analog and mixed-signal (A/MS) circuits with digital systems onto a single chip. This integration necessitates that these A/MS circuits be designed at advanced digital technology nodes, making them more susceptible to single-event effects (SEE) than previous technology generations. This dissertation presents a radiation-hardened-by-design (RHBD) framework to mitigate single-event effects in modern A/MS systems. The framework is centered around two hardening methodologies, hardening via charge sharing (HCS) and hardening via node splitting (HNS), that can be incorporated into continuous-time analog and mixed-signal circuits. Three novel RHBD techniques that utilize these hardening methodologies are introduced and experimental verified. The operational amplifier (op amp), a fundamental building block of A/MS circuit design, is used to experimentally verify the HCS techniques of differential charge cancellation (DCC) layout and sensitive node active charge cancellation (SNACC), and the HNS technique of peeled layouts. These techniques are verified using a through-wafer two-photon absorption (TPA) SE testing technique over three different process technologies ranging from 180 nm bulk CMOS to 32 nm SOI. Significant reductions in an op amp’s SE sensitive area can be obtained through the application of these techniques, with minimal design cost. This dissertation also presents a simulation study of several fundamental building block circuits commonly used in A/MS circuits in order to create design guidelines pertaining to the application of these three RHBD techniques, and the broader hardening concepts of HCS and HNS, to continuous time circuits. These findings and guidelines indicate that all differential analog signal paths should utilize some form of HCS, and that every A/MS circuit should use some form of HNS, in order to mitigate single-event transients.