Re: gEDA-user: IPC standard SMT footprints (0603, 0402 vs. RESC0603N etc.)

[Russell Dill <Russ.Dill@xxxxxxx>]

On Wed, May 25, 2011 at 2:40 PM, Colin D Bennett <colin@xxxxxxxxxxx> wrote:
> On Wed, 25 May 2011 23:03:06 +0200
> Gabriel Paubert <paubert@xxxxxxx> wrote:
>
>> This said, most capacitors look to have a square profile, but
>> resonance frequencies observed on microstrip line change between
>> mounting the layers parallel or perpendicular to the ground plane.
>> The problem is that, for most capacitors, it is very hard to
>> determine the orientation of the layers.
>
> That's interesting. ÂAre you saying that for high-frequency, critical
> signals, the orientation of the chip capacitor affects its performance
> in the circuit? ÂIs the SMD tape/reel packed in such a way that the
> capacitors are optimally oriented, ready for pick-and-place onto a
> PCB?
>

My understanding is that many resistors have a similar problem in that
the thin resistive strip is on the "top" or "bottom" of the device.
Mounting it upside down increases inductance.


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