Research And Implementation Of 24-bit High-precision ADC Test Technology

Analog To Digital Converter(ADC),as a necessary device for converting analog signals to digital signals,plays an important role in aerospace,precision measurement,wireless communication and other fields.Due to the needs of practical applications,ADC performance is constantly improving.High precision ADC has some problems such as long test time and high purity of test signal when using traditional test methods and equipment.Therefore,it is of great significance to study the test method of highprecision ADC according to the characteristics of high-precision ADC.The main research content of this topic is as follows:(1)High-precision ADC test scheme design.The traditional high-precision ADC test algorithm is studied,and the requirements of high-precision ADC test are analyzed.In view of the long test time and high source purity requirements of high-precision ADC test,a high-precision ADC test scheme based on ATE machine is designed.(2)High-precision ADC static parameter testing technology.The characteristics of high-precision SAR ADC with segmented architecture are analyzed,and the algorithm of segmented linear error identification is further studied,the INL of ADC is segmented,and the INL of each sub-segment is estimated respectively.The sum of the INL of each sub-segment is used as the actual INL of ADC.Compared with the traditional slope histogram,the number of sampling points is reduced by 10 times,and the testing efficiency of high-precision ADC is improved.(3)Design of Digital Signal Input Output(DSIO)module.According to the testing requirements of high-precision ADC,the DSIO functional logic design of ATE digital module is carried out,and the control and data acquisition of high-precision ADC can be completed by means of sequence triggering,and the acquisition vector can be compressed.(4)High-precision ADC test DIB(Device Interface Board)design.According to the test scheme,the channel isolation and selection circuit,low jitter clock circuit combined with PLL and divider,low noise power supply circuit,battery charge management circuit,low noise reference voltage circuit combined with reference filter,and analog channel conditioning circuit are designed and implemented.In this paper,a high-precision ADC test scheme is designed for 24 bit ADC AD7766.The test time is shortened by studying the algorithm of piecewise identification of linear error.At the same time,the hardware of the test system is designed and its main parameters are tested at last.ADC main parameters INL10.76 ppm,SNR 107.75 d B and THD-110.60 d B meet the test requirements,providing a complete set of solutions for high-precision ADC testing.