The Disquisition Of Test Method For Digital To Analog On Tester

A digital-to-analog converter(DAC)is a device that converts discrete quantized digits into continuous analog signals.It is a bridge connecting digital signals and analog signals.With the rapid development of electronic technology,digital-to-analog converts are developing towards high-speed higher and higher.Thereare more and more factors affecting the accuracy of the test,such as power drive,system clock,reliable grounding,test system and other factors,which will lead to the serious reduction of test performance parameters,thus making the test more difficult.Therefore,it's of great significance to explore high-precision DAC testing technology.This paper analyzes the base theory of DAC,introduces and summarizesits operating principle,performance index and testing principle.On this basis,the logical structure and electrical characteristics of a 12-bits voltage output DAC is researched.This paper proposes an automatic testing method of the proposed DAC,and realizes the fuse trimming in the wafer stage and automatic parameter testing in the final stage.The paper mainly studies the following contents:Firstly,this paper designes the PCB and determines the testing scheme of the fuse trimming in the wafer stage.For the PCB of the fuse trimming,this paper has considering how to enable the power integrity,how to design the PCB stacks and how to chose the decoupling capacitor.For the testing scheme of the fuse trimming,this paper uses the MSO module and the VBT script language of J750 integrated circuit test system.Three steps are adopted here.(1)The MSO module collects the output voltage values that corresponding to the convert points.(2)For the remaining steps,this paper programs with the VBT script language and realizes the corresponding operations in the J750 integrated circuit test system.Base on the output voltage values,the trimming code can be calculated and thus the place where to burn the fuse can be determined.(3)After all the fuses have been burned,the DNL of the DAC is tested.Secondly,by programming with the VBT script language in the J750 integrated circuit test system,this paper designs the test program for the DAC in final stage,according to the design requirement of the chip electrical parameters.This paper has tested the static parameter of the DAC in the whole temperature ranges.By comparing the results of static parameter with and without fuse trimming,the feasibility and reliability of the trimming algorith can be verifed.The test results show that,in the wafer stage,DNL is 2-3 LSB before trimming.It can be reduced to 0.2-0.85 LSB after trimming.INL is 2-3 LSB before trimming,it can be reduced to 0.5-2 LSB after trimming.This result shows that the DAC has met the design requirements after trimming.