Jeffrey,
could you write down for us an example of good stackup specification?
Something that gives enough freedom to the fab, so that they do a
competitive quote, but also keeps a rigorous functional spec, that is
portable when the board supplier changes.
Thanks,
Ioan
> -----Original Message-----
> From: Jeffrey Bush [SMTP:[log in to unmask]]
> Sent: Tuesday, July 13, 2004 10:15 AM
> To: [log in to unmask]
> Subject: Re: [TN] Board Stack geometry
>
> If needed for performance, the stackup on the drawing should only
> specify the required dielectric thickness and finished copper weights.
> The PCB can be constructed in many several methods to obtain the desired
> end thickness. If, for example, you spec out some plies of 2116 glass
> in an opening, and supplier B only uses 2165, this becomes an issue. If
> signal/performance integrity is not an issue in the design, leave it up
> to the PCB fab house and the compliance testing to your drawing
> requirement to ensure thermal and mechanical integrity is there.
>
>
>
> Jeffrey Bush
> Director, Quality Assurance and Technical Support
>
> 76 Technology Drive - POB 1890
> Brattleboro, Vermont 05302-1890
> Tel. 802.257.4571.21 Fax. 802.257.0011
> [log in to unmask]
> http://www.vtcircuits.com
>
>
>
> -----Original Message-----
> From: Roger Stoops [mailto:[log in to unmask]]
> Sent: Tuesday, July 13, 2004 9:05 AM
> To: [log in to unmask]
> Subject: [TN] Board Stack geometry
>
>
> This brings up a question I have had bumping around in my head for a
> while, for example:
>
> A pcb has been designed, assembled, tested, and now goes through FCC and
> CE emissions and susceptibility testing. The board stack was determined
> by the pcb vendor. The assembly passes first time. Purchasing or the
> EMS finds a less expensive yet reliable board house and buys production
> boards from this new house. The new house changes the board stack to
> their preferred lay-up.
>
> Would not this board need re-testing for FCC/CE
> emissions/susceptibility? For boards requiring this type of testing,
> would not a board stack specified on the print be required?
>
> TIA and much appreciated,
>
> Roger Stoops
>
>
> -----Original Message-----
> From: Jeffrey Bush [mailto:[log in to unmask]]
> Sent: Monday, July 12, 2004 8:40 AM
> Subject: Re: 7628 prepreg?
>
>
> Common type, stable, low resin content and likely predicable thickness
> is this is important. Otherwise PCB house should be left to determine
> the optimal stack for the board geometry and end use.
>
>
>
> Jeffrey Bush
> Director, Quality Assurance and Technical Support
>
> 76 Technology Drive - POB 1890
> Brattleboro, Vermont 05302-1890
> Tel. 802.257.4571.21 Fax. 802.257.0011
> [log in to unmask]
> http://www.vtcircuits.com
>
>
>
> -----Original Message-----
> From: Brooks,Bill [mailto:[log in to unmask]]
> Sent: Friday, July 09, 2004 5:08 PM
> To: [log in to unmask]
> Subject: [TN] 7628 prepreg?
>
>
> Bill Brooks
> PCB Design Engineer , C.I.D., C.I.I.
> Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 http://pcbwizards.com
>
> Why would a designer specify 7628 prepreg in the construction of a
> board? What characteristics are unique to it? Bill Brooks, CID
>
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