Design of TID-Tolerant ADCs in Multivoltage Domain Based on Body Effect

Total ionizing dose (TID) irradiation induces parameter drift and increases the leakage current in high-voltage analog-to-digital converters (ADCs) fabricated with thick-gate-oxide metal-oxide-semiconductor field-effect transistors (MOSFETs). In serious cases, these changes can affect the conversion performance of ADCs chips. In this study, the functional failures of high-voltage ADCs in multivoltage-domain circuits were examined after TID irradiation using simulation studies and experimental measurements. Accordingly, a circuit- and layout-based strategy was proposed to improve radiation tolerance. The reinforced circuit was fabricated by applying the characteristics of multivoltage domains and a combination of the body effect and TID effect. A charge pump unit was added to reduce TID irradiation. Furthermore, layout reinforcement was performed based on a commercial process by adopting an enclosed gate and isolation ring. The integral nonlinearity (INL) of the unreinforced device drifted by −18.11 least significant bit (LSB) after 30-krad (Si) irradiation. However, the INL of the reinforced device drifted by only 0.51 and 1.68 LSB after 30- and 100-krad (Si) irradiation, respectively. Hence, the total dose resistance of the reinforced device was more than ten times that of the unreinforced device. Consequently, a multivoltage-domain radiation-tolerant ADC with a TID tolerance of 100 krad (Si) could be generated.