Research on DOAL Module in Operational Amplifier Test

Operational amplifier is the most important unit circuit in analog circuit. With the development of miniaturization of integrated circuits, the testing of operational amplifiers has become more and more complex. The Dual Operational Amplifier Loop (DOAL) module of the automatic test system can provide high precision test resources and can be led out to the interface of the device under test for independent use, making the design of the test circuit simpler. According to the physical meaning of op-amp parameters and its test principle, the corresponding test circuit can be built by controlling the switches and relays inside the op-amp loop module, and the parameters of the op-amp can be tested accurately and automatically. The actual test results show that this method can guarantee the accuracy of the input offset voltage, output swing, open-loop voltage gain, supply voltage rejection ratio and common mode rejection ratio of the operational amplifier.