SI Analysis And Simulation Of High Speed Digital Circuit Based On HyperLynx

With the rapid development of the field of electronic design, the size of the high-speed digital circuit and the frequency of clock are increasing rapidly. SI(Signal Integrity) problems of high-speed digital circuits have also become more serious. However, using the method of SI analysis and simulation to design high-speed digital circuits can avoid SI problems effectively. In the paper, SI analysis and simulation are presented in a high-speed digital circuit by HyperLynx. SI problems are discovered, and a more comprehensive improvement measure is proposed. The main contents and researches are as follows:1. SI theory of high-speed digital circuits have been studied. High-speed digital circuits and SI are introduced. Transmission line model of distributed parameter characteristics is established, and two important transmission line equations are derived by theoretical analysis. Reflections, crosstalk and simultaneous switching noise analysis model are established, and their calculation formulas are deduced by theory. Their causes are explained, and solutions of these problems are proposed. The root cause SI problems are revealed, and the necessary theoretical foundation for future study is laid.2. SI analysis and LineSim have been presented in the three key features of a high-speed digital circuit by HyperLynx. According to the actual high-speed digital circuit, a corresponding circuit simulation model is established after setting the laminated structure and the characteristic impedance of the transmission line. According to the SI relevant theoretical knowledge of high-speed digital circuits, SI analysis and LineSim are presented in FPGA(Field Programmable Gate Array) configuration circuit, DDR3(Double Data Rate 3) high-speed memory circuits and TLK2711 high-speed data transmission circuit. The design method predicts the circuit reflections and crosstalk successfully, and these SI problems are eliminated by taking a termination resistor, shortening the line length, increasing the line spacing and other measures.3. SI analysis and BoardSim have been presented in the high-speed digital circuit by HyperLynx. First, all occurrences of SI network problems in the PCB(Printed Circuit Board) are found by the use of rapid global simulation. Second, networks of SI problems are extract to do SI analysis and Simulation by IBIS(Input/Output Buffer Information Specification) models after adjusting the stack parameters, and setting the correct voltage. The design method have found the circuit delay and crosstalk successfully. Combining with the theoretical analysis in Chapter two, a reasonable improvement measure is proposed. In order to solve the circuit SI problems, the high-speed digital circuit is modified.4. The test platform of circuit system has been built to test the high speed digital circuit system. High-speed digital circuits with issues of SI and improved circuit are tested after building a test platform. The specific object of the test mainly includes two aspects:the overall three key parts of the overall three key parts of high-speed digital circuit and the overall system. Test results:three key parts of high-speed digital circuit and the whole circuit system. Test results which are compared and analyzed verify that high-speed digital circuits with SI problems does not work, and it improves that circuit parts and the whole can work. It proves that SI problems in the high-speed digital circuits can be eliminated by SI analysis and Simulation, and it can ensure the normal operation of the circuit.