Yes!  Thank you, Paulo!  Interesting spread, to say the least - having such
a large difference between Level A and Level B, with such a small difference
between Level B and Level C.  It would make more sense if Level A was 0.3mm.
I also received information that they removed the PCB size variable.  That's
interesting, too.

Ray

----- Original Message -----
From: Paulo Egon Triebsees <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, September 23, 1999 1:37 PM
Subject: Re: [DC] IPC Specs - Errors?


> Hello Ray,
>
>
> >Can you tell me on what page of IPC-2221/2222 the fabrication allowance
> >appears on?  I do not have a copy, yet, but the people I have asked to
> check
> >say it is not in there.  I have IPC-D-275, which has it in Table 5-10 on
> >page 64.
>
>
> IPC 2221
> Table 9-1  Minimum Standard Fabrication Allowance for Interconnection
Lands
> at page 70
>
> Level A  0.4 mm
> Level B  0.25 mm
> Level C 0.2 mm
>
> Notes :
> 1- For copper weights greater than 1oz/sq.ft, add 0.05 mm minimum to the
> fabrication allowance for each additional oz/sq.ft. of copper used.
> 2 - For more than 8 layers add 0.05 mm
> 3 - See 1.6.3 for definition of Levels A, B and C. (Producibility Level)
>       Level A  General Design Complexity - Preferred
>       Level B  Moderate Design Complexity - Standard
>       Level C High Design Complexity - Reduced
>
> I hope this helps.
> Paulo Egon
>