Have a question about the pad size?
I am new about Cadence design. And now, I am making a footprint for a part. The pdf file shows you the min/average/max of each pin.
when you make a footprint, which number are you going to use? I know the bigger pad the better, but I still want to run tace between pins.
For example,e1 could be 8.20-0.55 =7.65mm or also could be 7.40-0.95=6.45mm. that makes a lot of different about the footprint~~
all also each pin width, should I use0.22 or 0.38 or ?
Have a look at www.pcblibraries.com This uses the IPC-7351 standard to build footprints automatically for many CAD tools incuding Allegro and OrCAD. You can design the footprint based on Min, Nom or Max values.
Leeya said:when you make a footprint, which number are you going to use?
I typically use the max # for size and nominal # for location.
Leeya said: I know the bigger pad the better
Not true, if the pad is too large then you will have too much solder paste and a greater possibility of shorts.
Leeya said: I still want to run tace between pins
I would not recommend trying to route traces between pins on fine pitch parts. You would need a very small trace and it is likely you will not have any solder mask covering the trace so you will have shorts.
You can also Web search for IPC-SM-782A.