Specifying stackups with
Speedstack
Application Note
AP517
Polar's Speedstack PCB and Speedstack Si controlled impedance stackup design systems provide formal and professional stackup design and documentation for all parties involved in PCB design and fabrication.
Providing full documentation of the completed stackup to the board supplier helps reduce the chances of miscommunication between PCB manufacturers and brokers, conveying clearly to the PCB fabricator the board designers' intentions, ensuring, for example, that the correct board and layer heights and materials are used in the build process. Speedstack can dramatically reduce the time for documentation and information sharing to a fraction of the time taken when employing traditional methods such as spreadsheet, word processor or presentation software.
Supply chain management
PCB
manufacturing supply chains are becoming longer — increasing in distance both in time and geography.
In addition, modern circuit board designs are
increasingly complex, multi-layer and often include
controlled impedance structures — the more complex the
stackup, the greater the potential for error. Board designers and fabricators are often
not in direct communication, particularly where board
fabrication is under the supervision of third party PCB
brokers.
Speedstack PCB is especially tailored for PCB fabricators and PCB brokers – any one with a requirement to design or communicate controlled impedance PCB stackups. Speedstack PCB customers are able to share stackups and read impedance requirements from designers who are using Speedstack Si.
Where the requirement is, however, for printed
documentation, Speedstack provides a high quality
solution in the form of its technical reports.
Speedstack's technical reports provide for sharing and documenting stackup information in a clear and consistent format. Material usage and graphical stack up views can be printed or shared electronically in a format that is easily read by both interconnect designer and fabricator. Speedstack’s customisable printouts make it easy to discuss alternate builds and pricing impacts with fabricators.
Flexibility in specification
Speedstack provides the flexibility to specify as loosely or tightly as required. For example, the Speedstack printouts below (Figures 1a to 1c) show details of Speedstack's Technical Report for a stackup specified with just the generic layer/drill and controlled impedance information.
Figure 1a Generic stackup
This report specifies overall board height, base and finished thicknesses (Figure 1a) along with the essential controlled impedance information for each structure — structure type, layer/region height, dielectric constant, trace widths, separation and impedance values and tolerances (Figures 1b and 1c).
Figure 1b Controlled impedance structures (layers and trace widths)
Figure 1c Controlled impedance structures (trace widths and impedance values)
This will allow the board fabricator to achieve the desired stackup with his own materials and provide boards meeting specification at the lowest cost.
The stackup below has been specified much more closely, with the material types stipulated expressly; the constraints imposed on the board manufacturer will ensure consistency of board fabrication - but at a higher cost.
Figure 2 Stackup with material (glass weave) types specified
Speedstack is used by PCB designers and fabricators worldwide to provide professional stackup documentation from end to end of their global and internal supply chains.
Click the link below to view a sample in PDF format