Design techniques for a stable operation of cryogenic field-programmable gate arrays

Area of Science:

• Cryogenic Engineering
• Integrated Circuit Design
• Digital Electronics

Background:

• Operating Field-Programmable Gate Arrays (FPGAs) at cryogenic temperatures presents stability challenges due to component performance degradation and power supply fluctuations.
• Long power supply lines and standard printed circuit board components exhibit instability at extremely low temperatures, impacting sensitive applications.

Purpose of the Study:

• To develop and demonstrate a firmware-based solution for stabilizing the internal supply voltage of deep-submicron FPGAs operating at cryogenic temperatures.
• To enhance the stability and performance of FPGAs in extreme cold environments for sensitive applications.

Main Methods:

• Designed a novel firmware that enforces constant power consumption to stabilize the FPGA's internal supply voltage.
• Implemented a tunable oscillator farm on the FPGA to measure and correct for digital logic speed variations caused by supply voltage fluctuations.
• Characterized component behavior at cryogenic temperatures to identify and address stability issues.

Main Results:

• Achieved significant stabilization of the FPGA supply voltage at cryogenic temperatures (15 K).
• Demonstrated improved performance of a reconfigurable analog-to-digital converter (ADC) implemented on the FPGA, with an enhancement of up to 1.5 effective bits.
• Validated the firmware's effectiveness in mitigating voltage drops caused by remote power supply.

Conclusions:

• The developed firmware technique offers a robust and versatile solution for stable FPGA operation in cryogenic environments.
• This method enables improved performance for sensitive cryogenic applications and is adaptable to various FPGA families and configurations.