I found the SN7485 and SN7486 but no SN7480 (or
at least no datasheet).
7480s were made by several manufacturers, but it was never a hugely
popular chip - sort of in the "second-string" functions of early 74xx TTL.
There are some real oddballs - 7459 is one (there was a thread on this a
few yars ago). I forget what it is - and I am not going to looking it up
again.
William Donzelli
aw288 at
osfn.org