Radiation Hardening of an SiGe BiCMOS Wilkinson ADC for Distributed Motor Controller Application

Abstract

The radiation robustness of a newly designed Wilkinson analog-to-digital converter (ADC) is being investigated. The ADC is a front-end design block within a cold capable, analog sense, application-specific integrated circuit (ASIC) manufactured using the IBM 0.5 μm silicon germanium (SiGe) BiCMOS 5HP process. The ASIC is part of a next-generation, cold capable, distributed motor controller architecture, which is a candidate for the next generation of Mars rovers. Its main function is to interface with various sensor types to monitor motor health (i.e., temperature, mechanical stress, pressure). While relatively well-hardened against total ionizing dose and destructive single-event latchup, the ADC showed some SEU (SET) sensitivity that is heavily dependent on its input channel configuration. For this study, we used a combination of experiments (pulsed-laser) and Cadence mixed-mode SEE simulations to explain the heavy ion irradiation results. We concluded that ADC input impedance configuration should be carefully controlled in the design of radiation-hardened systems for space.