I am new to Cadence SPB/Allegro, so there may be something simple I'm missing.I am trying to set up some basic library components, such as an LM317 regulator. The regulator comes in two styles we may use, a TO220 with 4 pins (3 pins and the heatsink), and a D-PAK with 3 pins. In the TO220 package, pins 2 and 4 (the heatsink) are the same. I want a schematic symbol with 3 pins connected to both possible footprints.In Part Developer, I can only connect a schematic pin to multiple footprint pins if I set it as a global pin, but then, as far as I can tell, I can't make it show up in the schematic symbol. Alternatively, I can create a footprint with the same pin number for pin 2 and the heatsink (maybe?), but then I can't reuse the footprint between components. Is there a better solution I'm missing?
If I understand what you need, you wish to short pins 2 & 4 on the footprint to a single pin on the schematic device. Please review the attached document and see if this helps.Essentially, you'll be adding a PACK_SHORT property to the symbol.Jerry
You may also consider the SourceLink Solution# 1816165
Thanks for the link, it solves half my problem.However, the result of following the instructions is to create a symbol that looks like it has only 3 pins, but actually has 4, which can then be associated with a footprint with 4 pins. The resulting symbol then cannot be used with a 3 terminal footprint. Is there any way to create a single, 3 pin transistor symbol that could allow either a 3 pin SOT-23 footprint or a 4 pin TO220 footprint to be chosen from a part table file, or do I have to suck it up and make two parts in my library?
Well ... from what you're trying to accomplish, this cannot even be consideredan asymmetrical part. Since you needed to match either a 3 --or-- 4 pinphysical package, the cleanest method would be to make 2 different componentsand reference their respective JEDEC_TYPE values for the footprints via thePTF files.Jerry