Research Of Signal Property On High-speed PCB Blind And Buried Via

With the development of integrated circuit, reducing the volume of electronic components, increasing the circuit layout density, high-speed circuit products have been widely applied to various fields. While the signal clock rate increase, there is a series of signal integrity problems including signal reflection, crosstalk, signal delay and timing error on the design of high-speed circuit PCB. So the design of high-speed digital system is becoming very important research topic in the field of electronic design base on signal integrity analysis. It not only can shorten the product development cycle, reduce the cost of development, but also can effectively and reliably improve the performance of the product.Via is an important part of high speed multilayer board PCB, make the electrical interconnection of different layer signal. As signal clock rate increases, the signal integrity problems on the via will influence the performance of the whole system. Effective analysis of signal characteristics of via, optimization of via’s the signal transmission quality, have very important and practical significance for the high-speed PCB design and engineering application.First of all, the main object of study with blind and buried vias based on the through via, describes the essence of blind and buried vias impedance characteristics of transmission line, based on the time domain reflection principle to carry on the analysis to the signal integrity of buried and blind vias problem, and by combining field and circuit theory and scattering parameters of the network, establishing the equivalent circuit model of high speed circuit buried and blind vias.Secondly, modeling and simulation the multi-layer PCB board of blind and buried via, by the electromagnetic simulation software HFSS. In the frequency domain and time domain, respectively by S parameter and characteristic impedance of TDR to the analysis of blind and buried vias frequency scattering characteristics and impedance continuity, compared with the through vias, and through vias of back drill; then analysis via physical parameters such as pad, anti-pad, aperture impact to signal characteristics on the blind and buried viasAt the end, proposing two optimization schemes for the blind and buried vias model, namely the method of multistage blind and buried vias and insertion of grounding vias by the theory. Improve the signal characteristics of buried and blind vias on the high-speed PCB board by the simulation analysis.