Multiple footprints in PCB Footprint property of OrCAD Symbol

Hi Patrick,

Yes ALT_SYMBOL is the ideal way. However, if you want multiple field values to be displayed for PCB Footprints and want schematic designer to choose one out of many from CIS Explorer while selecting the part and want it to show drop down for PCB Footprint value with multiple values, then this can be achieved by defining multiple values using delimiter in Database only.

Ex:

In database, using comm as delimiter, values for PCB Footprint can be defined as :

You can refer following article link from ASK Portal which are relevant for your query:

Article (11694374) Title: How to define and use ALT_SYMBOLS property in Schematic Capture to PCB Editor flow
URL: https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1Od0000000nYBhEAM

Article (20124578) Title: How can I make a field to have multiple values in CIS Explorer?
URL: https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1Od0000000sbkbEAA

Article (20508425) Title: How to change the delimiter for multivalued database field in Capture CIS
URL: https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1O3w000009ljvlEAA

I believe, it will help you to achieve your objective.

Hi Patrick,

Yes ALT_SYMBOL is the ideal way. However, if you want multiple field values to be displayed for PCB Footprints and want schematic designer to choose one out of many from CIS Explorer while selecting the part and want it to show drop down for PCB Footprint value with multiple values, then this can be achieved by defining multiple values using delimiter in Database only.

Ex:

In database, using comm as delimiter, values for PCB Footprint can be defined as :

You can refer following article link from ASK Portal which are relevant for your query:

Article (11694374) Title: How to define and use ALT_SYMBOLS property in Schematic Capture to PCB Editor flow
URL: https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1Od0000000nYBhEAM

Article (20124578) Title: How can I make a field to have multiple values in CIS Explorer?
URL: https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1Od0000000sbkbEAA

Article (20508425) Title: How to change the delimiter for multivalued database field in Capture CIS
URL: https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1O3w000009ljvlEAA

I believe, it will help you to achieve your objective.

Hello, 

thanks for the response.

the procedure with ALT_SYMBOLS is quite clear (However, as far as I know, it it not required to defined the side of the symbol, so you could also simply just use a comma separated value if it does not matter which footprint might be used for which side).

My question was more towards what are the best practices. Is it really so common that you use a PCB Footprint property with a list and that a schematic engineer decides which footprint is used in the layout? For me this is more a task for the layout engineer (who cannot do it if there is no ALT_SYMBOLS property) So I am basically looking for a guidance if this 'legacy' (this is how I declare it) is still recommended.

Is there any problem if both Properties are used, so a list for PCB Footprint and the ALT_SYMBOLS? any problem with the packaging process? what happens if these lists do not match?

Thanks

Patrick

Hi Pat, best practice is what basically works best for your design flow & there can be some variables with that.

From the perspective of Alt_Symbols, when you package your design & generate a netlist, the primary PCB footprint is used. In the PCB editor when placing symbols if alt_symbols are defined it is possible to use those instead of the primary symbol. A good case for this would be something like a typical SMD resistor that has as it's base regular rectangular pads, but the alt symbol may have rounded pads instead so as to aid in manufacturing.

In the CIS database what we do is have the first symbol defined in the Alt_Symbols field be the same as the primary PCB footprint name. The advantage here is when you look at the table you see consistency for both primary PCB footprint and also the alt symbol. Certainly you could have other symbols defined in the Alt_Symbols field too.

Best practice IMHO is to have the primary symbol that is known good to be the default. Ideally when an engineer is designing a schematic you would not want them changing the PCB footprint on the fly !.

Best Regards.