Design And Research Of An Effective Algorithm For ADC Linearity Testing

ADCs(Analog-to-Digital Converters),are one of the most important and the most widely used mixedsignal circuits in the world and the efficiently linearity testing of ADCs is an important and well known challenging problem facing the semiconductor industry.However,as the industry standard,the state-of-theart histogram method leads to long test time and high test cost,especially for high resolution ADCs.For this reason,it is important to explore an efficient ADC linearity testing method.In fact,many test methodologies have been proposed to reduce ADC linearity test cost in recent years.Unfortunately,these techniques reduced the test time by sacrificing test accuracy or test coverage.In this paper,according to the basic principle of the errors identification segmented model,we firstly propose an efficient algorithm to process the model.This model and the corresponding algorithm use coarse integral nonlinearity(INL)curve as the input,and break the curve into many segments.Every segment introduces a error term.With all the error terms,the accurate full code INL/DNL can be constructed.Besides,the coarse INL curve which is used as the input of the errors identification segmented model,can be easily obtained by using the histogram techniques.In addition,the concept of early diagnosis method is also used to improve the test coverage of the model.With above steps,the proposed ADC linearity testing algorithm termed as the errors identification segmented model and histogram method is formed.By using the proposed method,we can significantly reduce the required test data and hence test time while maintaining or even improving the precision of the standard histogram method.Besides,the proposed method has the advantages of being easy to implement and suitable for a variety of ADCs.In order to illustrate the superiority of the proposed algorithm,we firstly analyze the theory of the algorithm.Then,we set up a test platform based on automatic test equipment and designed linearity test flow to obtain lots of the actual measurement results.Both analyzed theoretical results and extensive actual measurement results validate the effectiveness,accuracy and efficiency of the proposed method.