WEBENCH® Tools: In Webench Filter Design, Select Alternative Part does not "stick".

Frank,

Thanks for bringing this to our attention. I managed to reproduce your observation and will report this to the stakeholder.

Just for curiousity, how valuable is the parasitic component selection to you?

How often do you use the select alternate parts to pick your parasitic components?

Alfred,

Thanks for your attention to this issue.  As to how valuable the selection ability is,  consider the following:

I am designing a breakout board to implement a multi-feedback filter design.  The design will have a non-filter differential input first stage followed by three stages for an order 6 filter implementation.  Because the design is intended to allow different designs to be implemented simply by BOM selections,  the critical filter parts must all be implemented with footprints for which both resistors and capacitors are readily available.  WEBENCH provides a database of components which all have the same parametric VALUE but differ with respect to other parameters (footprint, tolerance, material, etc.).  It is very useful to scan this list to select the appropriate footprint for each component.  Selection for other parameters (e.g. dielectric material) is also convenient.  My breakout design will implement high, low, and band-pass behavior by allowing certain components to be either a resistor or a capacitor.  Choosing a larger footprint than otherwise appropriate for a resistor allows replacement of that component with a capacitor.  One can not select too large a footprint because resistors will not be available.  There is a sweet spot for this use.

The WEBENCH design provides great calculation and optimization for component VALUEs needed to implement the various designs.  I can use that design information raw and manually view the component database to select the best footprint to use.  It would be valuable to be able to select the components from the database and then have this selection provide the BOM information in the design report.  Yes,  I can do the documentation outside of WEBENCH but why?  If you are going to provide a button in the GUI that says "Select Alternative Part" then I would expect that it would actually work???