A Radiation-Hardened SAR ADC with Delay-Based Dual Feedback Flip-Flops for Sensor Readout Systems

Area of Science:

• Electronics Engineering
• Radiation Effects on Materials
• Semiconductor Devices

Background:

• Analog sensor signals require accurate conversion to digital bits for system control.
• Radiation environments (space, nuclear) and high-reliability applications (automotive) degrade sensor readout systems, including ADCs, leading to malfunctions.
• Radiation effects like Total Ionizing Dose (TID) and Single Event Effects (SEE) pose significant challenges.

Purpose of the Study:

• To investigate an optimal Analog-to-Digital Converter (ADC) structure for radiation environments.
• To propose a radiation-hardened Successive-Approximation-Register (SAR) ADC design.
• To enhance system tolerance against radiation effects using specialized flip-flop structures.

Main Methods:

• Design and fabrication of a SAR ADC utilizing delay-based double feedback flip-flops.
• Utilizing a 130 nm complementary metal-oxide-semiconductor (CMOS) silicon-on-insulator (SOI) process.
• Experimental measurement of radiation tolerance in actual test facilities.
• Verification using compact transistor models reflecting radiation effects and radiation simulator CAD tools.

Main Results:

• The proposed delay-based double feedback flip-flops demonstrated enhanced radiation tolerance.
• The fabricated flip-flop was tested in radiation facilities, validating its performance.
• Simulations confirmed the effectiveness of the radiation-hardened SAR ADC design.

Conclusions:

• The proposed SAR ADC with delay-based dual feedback flip-flops offers improved tolerance to TID and SEE.
• This design is suitable for sensor readout systems operating in demanding radiation environments.
• The study provides a viable solution for reliable analog-to-digital conversion in harsh conditions.