The Testing And Trimming Of High-precision Multi-channel Successive Approximation ADC

High-precision ADC generally adopts SAR(Successive Approximation Register) structure to accomplish its design, because SAR structure has many prominent features such as low-power consumption, real-time conversion, easy attenuation about analog input etc. However, the production process exists inherent mismatch, packaging and other parasitic effects, and these factors will cause a problem that the DC accuracy of the ADC cannot reach 12 or more. Therefore, it become necessary to improve the matching of the device by trimming technology, and then the accuracy of the circuit will be increased.This thesis designed an ADC with 16-bit resolution and 6 channels, which belongs to the pattern of simultaneous sampling successive approximation, and finished trimming and electrical parameter testing about conversion errors based on the charge redistribution technology and Advantest’s 93000 mixed-signal test system. This ADC had both differential nonlinearity error and integral nonlinearity error which were less than ± 4LSB, and its DC accuracy was 14 or more, at the same time, it also had engineering production capacity.The main contents are as follows: Analyzed successive approximation ADC’s works and internal charge redistribution DAC`s basic trimming method, and researched converter`s nonlinearity error algorithm of testing and trimming. Developed parametric test program, and designed load board hardware used for testing and trimming according to the user manual of Advantest’s 93000. Designed and implemented test software based on Advantest’s 93000 and smartest environment, accomplished trimming about conversion time, reference voltage and differential nonlinearity error, and finally finished electrical parameters of the DUT. Optimized testing and trimming method in case of multi-channel approach, and controlled testing and trimming time within a few minutes to have the engineering capacity.The final results of this thesis can be used for production and test about simultaneous sampling precision successive approximation ADC with 16-bit resolution and 6 channels. This product has high-precision conversion and good consistency about electrical parameters.