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January 2004

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Subject:
Re: Mechanical stress on ceramic chip caps
From:
Ted Kong <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Tue, 6 Jan 2004 12:45:56 -0800
Content-Type:
text/plain
Parts/Attachments:
text/plain (63 lines) 
Hi Bob,

Is it possible to use smaller package components in
series or in parallels to avoid using 1812 packages?

Ted
--- "Crain, Bob" <[log in to unmask]> wrote:
> We build boards for space and they must be bonded
> and riveted to rigid
> aluminum frames to withstand the environments. We
> currently specify the
> IPC-6012 requirements which are 0.75% bow and twist.
>
> There is a concern that we may need to specify 0.5%
> bow and twist to prevent
> 1812 and possibly 1206 ceramic capacitors from
> developing cracks after the
> boards are attached to the frames.
>
> With our boards, .75% translates to a maximum of 45
> mils of bow and twist.
> Any thoughts on problem areas?
>
> The boards are normally .090 thick, 8-12 layers and
> polyimide.
>
>
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