Operational Amplifier Testing Is Implemented On J750 Test System

In the design verification stage,it is necessary to carry out a simple test on the chip,which is called verification test;after the wafer is manufactured,the wafer is tested,which is called intermediate test.At this time,the test equipment used is integrated circuit test system and probe table.After the wafer test is completed,the qualified wafer is packaged.After the package is completed,the test is conducted again.At this time,the required test equipment is the integrated circuit test system,which is called the integrated circuit test.The qualified products will enter the circuit screening process.In the screening process,it is necessary to carry out various tests on the integrated circuit,such as aging test,life test,static test,etc.After each test,the circuit to be tested needs to be tested,and the test phase is called screening test.Therefore,the test is an important part of the IC development process,and the test can not be separated from the test equipment,so the test equipment is particularly important.This paper analyzes the hardware structure of J750 testing machine,defines the hardware technical indicators of the test system;analyzes the software architecture of the test machine to determine the development process of the test program;analyzes the test parameters and test conditions of 10 operational amplifier circuits in detail;clearly knows the hardware resources required by the tester;thus determines that the hardware and software of J750 tester can meet the operational amplifier circuit Test requirements.On this basis,the test method of operational amplifier is studied in depth,and the test interface board is made.The auxiliary operation and release loop is established on the test interface board to realize the automatic test of operational amplifier on J750 testing machine.The main contents of this paper are as follows:① the development and verification of the program begin with the offset voltage which characterizes the important characteristics of the operational amplifier.The method of servo operation and release loop,the method of self closed loop and the method of changing power supply voltage are used to test the offset voltage on 750 testing machine.By analyzing the difference of self closed loop test,variable power supply voltage test and servo operation loop test,it is concluded that the test result is more stable and more suitable for the test of operational amplifier parameters by using the servo operation loop;the variable power supply method is more convenient and flexible for testing the operational amplifier parameters when the test equipment capacity is allowed;the self closed-loop test is relatively simple,but it is easy to occur The test data is abnormal and is not recommended for production testing.② Test the common mode parameters,such as voltage offset and voltage rejection,to ensure the accuracy of the test method.The common mode rejection ratio is tested by two methods,variable power supply method and common mode method.③The bias current of op amp is measured by closed-loop method.In the sampling current measurement method,the forward input and reverse input current are tested by precision resistance sampling and capacitor charging.④The output high-level voltage,output low-level voltage,output current and power supply current are tested by open-loop method.⑤ The modulation function of the digital channel of the testing machine is used to provide the required input signal to the operational amplifier,and then the conversion rate test is completed through calculation combined with the time measurement unit.Finally,the test program of operational amplifier circuit is developed on the domestic analog testing machine,and the test data of J750 and domestic analog testing machine are compared to verify the correctness of the test method on J750 tester and the stability of test data.