Keyword: pcb design, pcb , PCB supplier, PCB connector
Although around design for manufacturability (DFM) values PCB design, definitions, changes and technical disputes lot, all the questions are based on the chip. Of course, when we begin to consider 45 and 32 nanometer design, the chip DFM is a crucial requirement. However, concerns chip DFM, but ignored the more important technical needs: for the printed circuit board DFM. We all know that even one hundred percent perfect wafers, chip-to-chip communication link if any one component (such as encapsulation, connector or circuit board) is damaged, the target system may still not work properly. Many packages, connectors and PCB suppliers may be forced to chase the system designer to control their machining tolerances.
However, unless all vendors tighten specifications, such as a tolerance of plus or minus 5 percent of the PCB connectors plus or minus 10% tolerance of the system may be ineffective. In order to optimize system design, designers need to study the causal relationship between each component. So far, we have not DFM tools to handle that sort of design problems. In the pre-layout design stage, high-speed systems PCB design or signal integrity engineers usually only a limited Spice simulator. PCB design To ensure the system is working properly, you need to be able to cover all machining tolerances boundary conditions for simulation PCB design. For example, PCB changes in the metal line width, dielectric stack height, dielectric constant and loss tangent of all of them affect impedance and attenuation. However, only the larger company's engineers would have the resources to customize their PCB design own scripts to perform thousands of simulation work, and then process the results. Even so, on what kind of variable scanning is still not well-defined standard.
The most obvious is the lack of packaging and connectors boundary model. For high-speed design, these models can only be associated with the frequency of the S-parameters to precisely define. However, very few vendors provide good S-parameter models, not to mention the wide range of frequencies within the boundaries of the model PCB design. In the post-layout verification stage, the need for complex precision PCB extraction and simulation to calculate the exact angle and bending. However, almost no tools available. Obviously, you need a common PCB design and verification methods. So, what do we need? Let's focus on two areas. For pre-layout design, for example, PCB design a GUI-driven circuit diagram input editor, enabling the designer to easily enter each component changes, simulation and process the results, the report generation and impact of each variable.
For post-layout verification, DFM tools need to be able to automatically adjust the layout to cover boundary conditions, PCB design using a fast full-wave extractor to extract parasitics in circuit simulation using I / O transistor boundary model simulation. Only when the designers in the PCB design and verification are considered within the work is poor, they can say to do design for manufacturability. Only when the tool vendors recognize the chip just subsystems - such as PCB - part, then the DFM and ultimately to the development of the end product with the customers really correlate PCB design.
