1 Dynamic current activity measurement for integrated circuit emission model M. Emin Baak, Ayten Kuntman Istanbul University, Faculty of Engineering, Department of Electrical & Electronics Engineering, 34850, Avclar, Istanbul, Turkey mebasak@istanbul.edu.tr, akuntman@istanbul.edu.tr Abstract This paper describes the current activity measurement and modeling of integrated circuits for electromagnetic conducted emission. In this study, a test circuit including the MC9S12XMAG-family microcontroller was designed and measurements were made to confirm the applied measurement techniques. Moreover, internal current was obtained from the measured external current which is described as a dynamic current activity on the die. The input impedance measurements were performed in the frequency range from 1MHz to 2GHz. The passive distribution network was extracted with the differential evolution algorithm from the measured impedance – frequency curve and results were compared with the measurements. The external current was measured by the spectrum analyzer has been used to obtain the internal current of the die. Extracted passive distribution network and internal activity component values have been given to obtain the integrated circuit emission model. 1. Introduction Electromagnetic compatibility (EMC) is the ability of an electrical or electronic product or system can operate accurately in the intended environment without degradation of performance due to unintentional electromagnetic interactions. Passing every day a new electronic product is entering into our lives. Increasing integration of electronic products and/or systems are becoming more complex nowadays. The power and frequency range electronic devices were increasing and creating a more severe and uncontrollable electromagnetic environment. It is difficult to operate in the intended environment without causing performance degradation due to unintentional electromagnetic effects. The lately developed integrated circuits (ICs) generated the amount of parasitic emissions due to advances in digital and semiconductor technology, higher clock speeds, more complex circuits, upper dynamic current consumption, and insufficient design methods. Highest in a number of the EMC related problem concentrated on the external part of the IC, despite the fact that, ICs have important functions in many cases of the electromagnetic compatibility of an electronic system. In this study, internal part of the IC core has been focused on. EMC is generally checked at the end of the design cycle, before the IC is placed on the printed circuit board. If the emission level is higher than the expected, the design will be done again and this will be caused by loss of time and money. * This study was supported by the Istanbul University Scientific Research Projects Unit. Project Numbers: 12813 and 13326. Therefore, a model is needed to predict the EM compliance precisely and swiftly. Various electromagnetic models have been generated to predict the behavior of the ICs in electromagnetic environment [1-14]. Integrated circuit emission model (ICEM) [1- 9] and Linear equivalent circuit and current source (LECCS) model [1, 10] has been used for prediction of electromagnetic emission of ICs. Input/Output buffer information specification (IBIS) has been used for printed circuit board (PCB) analysis is the other emission model [11, 12]. An I/O interface model for integrated circuit (ICIM) model has also been used in board design [1,13]. In our previous study [2], a test circuit containing PIC16F628 was designed and measurements were made to obtain the input impedance of the power supply pin of the microcontroller. In [2], the genetic algorithm was used to obtain the model. In this study, a test circuit containing the MC9S12XMAG-family microcontroller was designed and measurements were made to confirm the applied measurement techniques as defined in Section 2 [1, 2]. The test circuit used in previous work [2] is changed to show that this modelling approach can be approved to any other integrated circuits. Network analyzer was performed using the test circuit measurement and no voltage was applied to the circuit during the measurements. In this way the global impedance of the PCB, conducted path, SMA connector and microcontroller core was obtained. Then, the impedance of the PCB, conductive path between the power supply pin and SMA connector, and SMA connector was removed by the de-embedding technique. Passive distribution network (PDN) was obtained from the measured curve. The differential evolution algorithm used for the modelling and it shows very good agreement with the measurement results. The external current, measured with the spectrum analyzer, was used to obtain the internal activity of the IC core. The effect of the amplifier, which was used to obtain the current measurements, was deleted by the de-embedding technique. Obtained passive distribution network and internal activity (IA) of VddPLL power supply pin is modelled by combining. 2. The passive distribution network measurement and modelling The integrated circuit emission model’s objective is to be proposed electrical modelling for integrated circuit internal activities [1-9]. This model will be used to evaluate electromagnetic behavior and performance of electronic equipment. Three ICEM components are needed to describe an ICEM block which is shown in Fig. 1. i. The passive distribution network component ii. The internal activity component iii. The inter-block coupling component 385