I am in the process of creating a BGA footprint.

This BGA is a 17x17 ball package - for this discussion, the particular 
dimensions are irrelevant.

My question... the IPC footprint generator (Altium) starts the alpha 
section of numbering with the letter 'A' and then goes sequentially to 
B, C, D, E, F, G, H - and skips I. The next one is J, etc.

Is this by some 'standard' or arbitrary. I have seen this done through 
the years with the skipping of the letters 'I', 'O', and... I don't 
remember the others, but think that there are a few others.

I'm looking for some sort of 'reference' or published IPC statement 
(JEDEC perhaps?) that says, 'skip the following letters when creating 
BGA footprints'.

(I hope my ramblings make sense...)

-- 
Regards,

James Jackson, CID
Oztronics