Design Of Printed Circuit Board Verifying Tools Based On ODB++

With the size of the IC process reducing to less than 20 nm, supply voltage of single-chip is decreasing while the current density continues increasing, and the working frequency has reached to more than 10 GHz, which makes board-level power integrity and signal integrity problems increasingly serious. Before the production of PCB, the electrical rule checking and signal integrity verifying through the PCB layout become the key factors that determine whether the high-speed board-level system can be made successfully from design to manufacture at the first time. However, to high speed, high density PCB board-level system, it is impossible to complete the PCB layout DRC checking, power integrity and signal integrity verifying only through personal experience or artificial means.Although the commonly used EDA softwares in today’s market, such as Cadence’s SI simulation software, have already contain the function of PCB layout verifying, they lack of the ability to simulate the entire board. In addition, although the function modules of different EDA software have different features, there does not have a unified file exchange interface specifications among all software platforms, which make it difficult to share resources among different EDA software development platforms and make it impossible to achieve optimization of entire PCB layout design. Therefore, in order to complete the simulation of the entire PCB layout and the data exchange among various EDA softwares, it is very important to develop a PCB layout automatic verifying platform that has unified data exchange interface.It is well known that Gerber is a standard in the PCB data industry. Even after continuous improvement, the design complexity causes Gerber files can not be able to describe these contents that relate to PCB production and assembly. In recent years, due to the unreasonable data exchange, the loss in electronics industry every year is as high as billions of dollars, and there are more than 3% cost of PCB processing wasted on data processing and verification. In addition, non-uniform data format makes designer and manufacture repeated interaction, resulting additional cost of time and money. Abroad are actively planning new PCB data exchange standards, the three candidate formats approved in entire electronically industry are that: Gen CAM(generic computer aided manufacturing) of American Package Interconnect Association(Institute for Packaging and Interconnect,IPC), Valor’s ODB++, and EDIF400 of American Electronics Industry Association(Electronic Industries Association, EIA). According to statistics, EDA softwares, in current, which can export ODB++ file format have as many as a dozen, and have considerable competitiveness in market. So it will be a good choice to take ODB++ as the foundation of software development.In view of the current situation described above and the development situation of PCB data exchange standard, this paper makes a deep study on the design rules of ODB++ file and its structure, and puts forward a detailed method which could transform ODB++(file of engineering system board) into editable PCB layout. In addition, Pyhton scripting system is used to edit PCB layout rules, and a specific secondary Client/Server mode of database system is used to manage rules, which can realize the accumulation of experience and enrich the rules. By using this software, Engineer’s PCB design can significantly improve the probability of success of one-time making of PCB; hence, system cost is reduced. Finally, this paper makes a detailed introduction to the reviewing step of the software and enumerates some transformation examples which fully demonstrated the validity and importance of this research.