According to information I have, the C0 means zero nominal tempco, and
the G means +/-30 ppm. There are various other letters (unfortunately
not in order) representing tolerances from +/-10 to +/-2500 ppm.
(There's also the letter O meaning "not specified" and P meaning "see
applicable specification".) +/-60 is H, so a 0 +/-60 ppm part would be
C0H, not C0G. This series of suffix letters is used for temperature
compensating types (e.g., M7 (P100), R2 (N220)) as well, so R2G would be
-220 +/-30 ppm, M7H would be +100 +/-60 pmm, etc.

Roy Lewallen, W7EL

Tom Bruhns wrote:

Sorry to say that I don't have a recommendation for a vendor for small
quantities of the 1% parts, but how many did you need? I know I have
some of the 1.0nF 0805s, and might get lucky on the others too. I
have a whole bunch of some value fairly close to 4.7nF, and I'm just
not remembering which it is. Might be 3.9, might be 5.6 or 6.8, if
not 4.7. Anyway, if you're not looking for too many, I'd be happy to
help you out.

But even if you buy a bunch of 5% ones, that might not be a bad way to
go. I just measured about 20 470pF 5% ones I happened to have on my
desk, and they were between 468 and 488, about +/-2% from the
midpoint.

I'm not remembering where I saw the 60ppm number. It surprised me,
though, and I made a mental note to always check the specs on the caps
I'm using, if it's important. It was fairly recently, and it was a
surprise because I had always equated 30ppm with NPO/C0G. I just did
a Google search for "C0G 60ppm" and got several hits, but in looking
at some of them, I found 60ppm associated only with NPO, and not with
C0G, so perhaps I'm wrong about C0Gs, at least. I'd be happy to be
wrong in this case! A little further looking suggests that EIA CG or
C0G officially must be +/-30ppm max, and EIA CH is +/-60ppm.

Cheers,
Tom