[SI-LIST] Re: PCB stackup material properties for a fee?
- From: "David Hoover" <dhoovy@xxxxxxxxxxxxx>
- To: <r.moser@xxxxxxxxxxxxxxxxx>, <tony_dunbar@xxxxxxxxxxx>,<si-list@xxxxxxxxxxxxx>
- Date: Sun, 18 Apr 2004 14:03:43 -0700
Russell's email on this really makes the most sense. I completely understand
being concerned if you get a charge request when asking to have those values
for the materials being used on a project. I guess the real question lies
with what
was the "rest of the information" around the original question?
My thoughts on this would be if you had a project built and the designer
then asks
for the information to be taken off the live PCB (instead of a test coupon)
that could
have some bearing on this discussion. Also, how many test measurements would
be
required (for the $100 fee)? The most commonly used TDR in PCB fabrication
is not
capable of measuring loss tangent and the Er' measurement on this unit is
probably not
the best (when compared to a DSO TDR inside a lab environment). Now
frequency
has been mentioned in some other emails on this topic. TDR is "time domain"
and
really is somewhat different than "frequency domain" (VNA's). Your average
PCB
fabricator does not have access (or own) a VNA and would have to subcontract
that service. If frequency was a part of the original request maybe that
helped drive
the cost parameter. (?) If the original request was ONLY for the relative
electrical
performance information on the raw laminate material which would come from
the
laminate manufacturer, then I agree. The $100 charge was not competitive
with
the rest of the industry.
Regards,
David Hoover
http://home.earthlink.net/~dhoovy
----- Original Message -----
From: "Russell D. Moser" <r.moser@xxxxxxxxxxxxxxxxx>
To: <tony_dunbar@xxxxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
Sent: Wednesday, April 14, 2004 5:53 PM
Subject: [SI-LIST] Re: PCB stackup material properties for a fee?
> Was the information more than they normally supply? For example, we note
> that many data for dielectric, loss tangent are spec'd at the 100's of
MHz,
> some around a GHz; I could envision a backcharge for testing a coupon at
> some "custom" frequency.
> If this wasn't your case, find a new board vendor.
>
>
> Regards,
> _________________________
> Russell D. Moser, Principal
> The Orion Group
> r.moser@xxxxxxxxxxxxxxxxx
> www.theoriongroup.net
> 717.503.6682 (cell)
>
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On
> Behalf Of Dunbar, Tony
> Sent: Wednesday, April 14, 2004 6:33 PM
> To: 'si-list@xxxxxxxxxxxxx'
> Subject: [SI-LIST] PCB stackup material properties for a fee?
>
> Has anyone experienced - or care to comment upon - a board vendor asking a
> fee ($100 in this case) to supply dielectric property information (Er,
Loss
> Tangent, etc.) to an end-user board designer?
>
> Thanks
> Tony
>
>
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