PCB Technical - Combination of high-speed digital PCB and EDA software

This article introduces a design method of high-speed digital signal PCB board based on signal integrity computer analysis. In this design method, the PCB board-level signal transmission model is first established for all high-speed digital signals, and then the solution space of the design is found through the calculation and analysis of signal integrity, and finally the PCB is completed on the basis of the solution space. Board design and verification.

As the output switching speed of integrated circuits increases and the density of PCB boards increases, signal integrity has become one of the issues that must be concerned in the design of high-speed digital PCNs. Factors such as the parameters of the components and the PCB board, the layout of the components on the PCB board, and the wiring of high-speed signals will cause signal integrity problems, resulting in unstable system operation or even no operation at all.

How to fully consider the signal integrity factors in the PCB design process and take effective control measures has become a hot topic in the PCB design industry today. The high-speed digital PCB board design method based on signal integrity computer analysis can effectively realize the signal integrity of PCB design.

At present, there is no integrated EDA software in the PCB design industry to complete the above-mentioned design method, so it must be realized through the combination of some general software tools.

Use general SPICE software (such as PSPICE, HSPICE, etc.) to establish SPICE models for discrete and passive components and transmission lines on the PCB, and debug and verify them.

Add the SPICE/IBIS models of various components and transmission lines that have been obtained to general signal integrity analysis software, such as SPECCTRAQuest, HyperLynx, Tau, IS_Analyzer, etc., establish the SI analysis model of the signal on the PCB board, and perform the signal integrity Analysis and calculation of sex.

Use the database function that comes with the SI analysis software, or use other general-purpose database software, to further sort and analyze the results of the simulation operation, and search for the ideal solution space.

The boundary value of the solution space is used as the basis for PCB circuit design and the constraint condition of layout design, and EDA software for general PCB design, such as OrCAD, Protel, PADS, PowerPCB, Allegro and Mentor, is used to complete the PCB circuit design and layout design.

After the PCB layout design is completed, the parameters of the actual design circuit (such as topology, length, spacing, etc.) can be extracted automatically or manually through the above layout design software, and sent back to the previous signal integrity analysis software for wiring. SI analysis to verify whether the actual design meets the requirements of the solution space.

After the PCB board is manufactured, the correctness of each model and simulation calculation can be verified through the measurement of experimental instruments.

Summary of this article: This design method has strong practical significance for the design and development of high-speed digital PCB boards. It can not only effectively improve the performance of product design, but also greatly shorten the product development cycle and reduce development costs. It is foreseeable that with the continuous improvement and improvement of signal integrity analysis models and calculation analysis algorithms, PCB design methods based on signal integrity computer analysis will be more and more applied to the design of electronic products.

This article introduces a design method of combining high-speed digital PCB board and EDA software based on signal integrity computer analysis.