| With the requirements of the smart phone system to the signal transmission rate and the frequency of the clock frequency, the high data rate transmission protocol is also came into being. USB forμm USB-IF released the new USB 3.1 specification in 2013, the theoretical data transmission speed can reach 10Gbps, is 20 times the transmission speed of USB2.0, and compared to the USB3.0 standard is also more than doubled. However, when such a high speed signal is go through with the flexible circuit board, it will have signal integrity problems, such as signal delay, reflection, attenuation, crosstalk, dispersion, etc.. Therefore, signal integrity issues become the key factor in the application of USB 3.1 technology in the mobile phone system, and it’s also one of the key issues in the design of high speed digital system.This paper in view of the characteristics of USB bus, based on the advantage of USB type C interface to discuss application USB 3.1 technology in mobile phone flex interconnection line the key is signal integrity problems. Firstly, analyzed the characteristics and process of the flexible circuit boards Combine with transmission line theory and performance, analyzed the key factor of the transmission line impedance control and insertion loss are the effect of the signal integrity of the high frequency transmission line. And further discussed how to improve the signal integrity of USB transmission line based on the existing process and no increase in cost. The effect of high frequency signal on the temperature rise and EMI control of USB power supply line is also studied. Finally, complete the smart phone USB3.1 flexible transmission line in the circuit design, layout and wiring, and simulated and analyzed usb3.1 signal line impedance value and the insertion loss. Measurement the actual manufacturing circuit board usb3.1 signal impedance date, use Eye Diagram to check the signal quality. Through the research of this project, the signal integrity problem of USB3.1 signal line is solved, and established the flexible circuit board design rules for apply USB3.1 technology in mobile phone. |
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