Genetic Algorithm-based Capacitor Mismatch Calibration Scheme for SAR ADCs

Researchers at Beijing Jiaotong University have proposed a novel capacitor mismatch calibration algorithm based on genetic algorithms. The algorithm optimizes the effective number of bits (ENOB) of the analog-to-digital converter (ADC), transforming the capacitor mismatch problem into an optimization problem that can be solved using a genetic algorithm. The proposed scheme was verified through experiments on a 312.5 MS/s 6-bit sub-ADC, demonstrating an ENOB of 13.2 bits, a significant improvement of 2.1 bits.

Key Takeaways:

• The proposed capacitor mismatch calibration algorithm uses genetic algorithms to optimize the ENOB of the ADC.
• The algorithm transforms the capacitor mismatch problem into an optimization problem, allowing for solution through genetic algorithms.
• The proposed scheme was experimentally verified on a 312.5 MS/s 6-bit sub-ADC, achieving an ENOB of 13.2 bits.
• The experimental results demonstrate a significant improvement of 2.1 bits in ENOB compared to the original design.
• The algorithm was implemented on a 55-nm CMOS process, showcasing the feasibility of the proposed scheme in high-speed ADC designs.
• The capacitive digital-to-analog converter (CDAC) in the proposed scheme adopts an interdigitated structure to reduce capacitor mismatch.
• The algorithm was validated through experiments on a 14-bit behavioral model, demonstrating its effectiveness for high-precision SAR ADCs.

Statistics:

• ENOB of 13.2 bits achieved through the proposed scheme, representing an improvement of 2.1 bits.
• Experimental results on the 312.5 MS/s 6-bit sub-ADC showed an SFDR of 46.7dBc at an input frequency of 150.146 MHz.
• The algorithm was implemented on a 55-nm CMOS process, showcasing the feasibility for high-speed ADC designs.
• The capacitive mismatch problem was transformed into an optimization problem through the proposed algorithm.
• The genetic algorithm-based scheme was experimentally verified through multiple iterations, demonstrating its effectiveness.

Sources:

• A Genetic Algorithm-based Capacitor Mismatch Calibration Scheme for Sar Adcs. Microelectronics Journal, 2025;161.
• Beijing Jiaotong University, School of Electrical and Information Engineering, Beijing 100044, People's Republic of China.
• Yuzhen Zhang, Xuan Guo, Hanbo Jia, Linzhen Wu, Dandan Wang, and Xinyu Liu (Additional authors for this research).
• Li Luo (Lead author, contact for additional information).
• Microelectronics Journal (Elsevier) - www.journals.elsevier.com/microelectronics-journal/
• Elsevier Sci Ltd (Publisher) - www.elsevier.com