J4 ›› 2015, Vol. 42 ›› Issue (6): 61-65+87.doi: 10.3969/j.issn.1001-2400.2015.06.011

• Original Articles • Previous Articles     Next Articles

Analysis of non-ideal factors and digital calibration for highresolution SAR ADCs

CAO Chao;MA Rui;ZHU Zhangming;LIANG Yuhua;YE Qian   

  1. (School of Microelectronic, Xidian Univ., Xi'an  710071, China)
  • Received:2014-10-17 Online:2015-12-20 Published:2016-01-25
  • Contact: CAO Chao E-mail:chao_cao@126.com

Abstract:

An analysis of capacitor mismatch in a high resolution successive approximation register (SAR) analog-to-digital converter (ADC) is described. The results show that the mismatch of capacitors and the parasitic capacitance in the LSB capacitor array have a significant influence on the resolution of ADC while the parasitic one in MSB array has little influence on the precision. A 16-bit SAR ADC high-level model is designed and a background digital calibration is proposed to calibrate the errors due to the mentioned sources. Simulation results indicate that the ENOB(Effective number of bits) after calibration is above 15 bit with a probability of more than 90%. The availability of this calibration method is verified, so it can be utilized to calibrate high-resolution SAR ADC.

Key words: high resolution analog-to-digital converters, successive approximation register analog-to-digital converters, capacitor mismatch, digital calibration, high-level model