Study On The ESD/EFT Immunity Test And Modeling For MCU

As a core component of modern electronic products, EMC performance of MCU often plays a vital role in the electronic systems. The EMC-related robustness of an individual chip against electromagnetic interference has a direct impact on the robustness of the whole design. With the rapid development of IC technology and shrinking of IC characteristic dimensions, the operating frequency and integration of MCU are increasing and the supply voltage becomes lower. As a result, the electromagnetic sensitive of MCU against to external electromagnetic interference gets increasingly high. One of the main interferences for MCU is transient impulse interference. For the requirements of EMC performance, it is urgent to present EMC test methods for evaluating the transient impulse immunity level of MCU. In order to better understand the failure mechanism of MCU to transient impulse interference and save costs that are spent to improve the EMC performance of MCU products, it is meaningful to model transient impulse immunity of MCU for predicting its immunity level.Firstly, this paper introduces the signal characteristics and the coupling mechanism of transient impulse interference and so on, including its test models and Spice models, the harm of this interference to MCU and the corresponding testing standards. The immunity modeling methods of MCU are also presented. The creativity is that proposing an improved EFT method, based on the ESD and Langer EFT test models. Those models are verified by simulation and measurement.Secondly, two transient impulse immunity test methods for ESD and EFT are analyzed from aspects of setup of test environment, test software and hardware configuration and test procedures. Based on this, a improved EFT test method for MCU is proposed. Comparison experiments between improved EFT method and the original EFT method are carried out to prove the feasibility of new method.Finally, transient impulse immunity modeling scheme for MCU is proposed. Immunity model based on an MCU product is established by the parameter extraction of the test board and power distribution network. Langer EFT test is performed to verify the accuracy of the model. At last, the model is able to accurately predict the voltage at power-supply pins.